Evaluate if x =3 and y = -2

x2+2xy−4y

Answer:

Step-by-step explanation:

=-5 +4

= -1

put a dot on -1 and go from -5 to -1 and then from -1 to -5

Answer:

Step-by-step explanation:

Given the expression 4sinB = 3sin(2A+B), we are to show that the expression 7cot(A+B) = cotA

Starting with the expression

4sinB= 3sin(2A+B)

Let us re write angle B = (A + B) - A

and 2A + B = (A + B) + A

Substituting the derived expression back into the original expression ww will have;

4Sin{(A + B) - A } = 3Sin{(A + B)+ A}

From trigonometry identity;

Sin(D+E) = SinDcosE + CosDSinE

Sin(D-E) = SinDcosE - CosDSinE

Applying this in the expression above;

4{Sin(A+B)CosA - Cos(A+B)SinA} = 3{Sin(A+B)CosA + Cos(A+B)sinA}

Open the bracket

4Sin(A+B)CosA - 4Cos(A+B)SinA = 3Sin(A+B)CosA + 3Cos(A+B)sinA

Collecting like terms

4Sin(A+B)CosA - 3Sin(A+B)cosA = 3Cos(A+B)sinA + 4Cos(A+B)sinA

Sin(A+B)CosA = 7Cos(A+B)sinA

Divide both sides by sinA

Sin(A+B)CosA/sinA= 7Cos(A+B)sinA/sinA

Since cosA/sinA = cotA, the expression becomes;

Sin(A+B)cotA = 7Cos(A+B)

Finally, divide both sides of the resulting equation by sin(A+B)

Sin(A+B)cotA/sin(A+B) = 7Cos(A+B)/sin(A+B)

CotA = 7cot(A+B) Proved!

Answer:

The derivative of the function f(x) = -5x+3x is ---->  -2

Step-by-step explanation:

Answer:

Step-by-step explanation:

The standard form of writing a scientific notation is expressed as [tex]a.b*10^n[/tex] where a, b and n are integers. Note that a, b and n cannot be a fraction. When writing in scientific notation, the value of 'a' must not be equal to zero and it must not be a 'two digits values' but just 'a digit value'.

Based on the above conclusion, the following numbers are correctly written in scientific notation.

1×10⁻⁴ and 9.8×10⁵

- The expression 10.8×10 −3 is not correctly written because the value of a on comparison is a two digits number i.e 10.

- Also, 0.54×10^6 is not correctly written because a is zero on comparison

- 7.6×10 2.5 is not correctly written because the power is a decimal number i.e 2.5. We must only have an integer as the degree.

Part A

Her steps were

[tex]-2 \frac{5}{6} \div 1 \frac{1}{3}\\\\-\frac{17}{6} \div \frac{4}{3}\\\\-\frac{6}{17} \times \frac{3}{4}\\\\-\frac{6\times 3}{17\times4}\\\\-\frac{18}{68}\\\\-\frac{9}{34}\\\\[/tex]

Kelsey made a mistake on line 3. Note how the 17/6 flips to 6/17. This is not correct. You keep the first fraction the same, but you do flip the second fraction. This only applies when you divide two fractions.

The third step should look like [tex]-\frac{17}{6}\times \frac{3}{4}[/tex]

=======================================================

Part B

Here's what she should have written

[tex]-2 \frac{5}{6} \div 1 \frac{1}{3}\\\\-\frac{17}{6} \div \frac{4}{3}\\\\-\frac{17}{6} \times \frac{3}{4}\\\\-\frac{17\times 3}{6\times 4}\\\\-\frac{51}{24}\\\\-\frac{17}{8}\\\\[/tex]

If you want to convert that improper fraction to a mixed number, then you could do something like this

[tex]-\frac{17}{8} = -\frac{16+1}{8}\\\\-\frac{17}{8} = -\frac{16}{8}-\frac{1}{8}\\\\-\frac{17}{8} = -2 \frac{1}{8}\\\\[/tex]

Or you could divide 17 over 8 using long division to get 2 remainder 1. The 2 is the quotient that goes to the left of the 1/8. The remainder of 1 is the numerator of 1/8.

3920|2

1960|2

980|2

490|2

245|5

49|7

7|7

1

[tex]3920=2^4\cdot5\cdot7^2=(2^2)^2\cdot5\cdot7^2[/tex]

It's 5

Answer:

C. Point A lies on ray BC

Step-by-step explanation:

Points A and C can be connected by a segment which would be a measure of the distance between the points. Locating point B between AC, makes the three points lying on segment AC.

A ray extends from a point to infinity, a line extend to infinity on both sides, while a segment is known to have two endpoints. Therefore, points AC are the end points of the segment AC, and point B between this segment confirms that point B lies on the segment AC. Therefore, Point A lies on ray BC is not correct.

here is the answer for question ii

The product of (4z² + 7z – 8) and (–z + 3) is -4z³ + 5z² + 29z - 24

(4z² + 7z – 8) and (–z + 3)

= -4z³+ 12z² - 7z² + 21z + 8z - 24

= -4z³ + 5z² + 29z - 24

Therefore, the product of (4z² + 7z – 8) and (–z + 3) is -4z³ + 5z² + 29z - 24

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Answer:

cot α = 1/tan α = 1/2.4 = 0.42

Step-by-step explanation:

cot α=0.42

sin α = 0.92

we know that  cot α = 1/tan α

thus,

cot α = 1/tan α = 1/2.4 = 0.42

we know that

sin(x)=tan(x)1+tan2(x)√

[tex]\ sin(\alpha )=tan(\alpha )/\sqrt{ 1+tan^2(\alpha )} \\sin(\alpha )= 2.4/\sqrt{1+2.4^2} = 2.4/\sqrt{1+5.76}\\sin(\alpha )= 2.4/\sqrt{6.76} = 2.4/2.6 = 12/13 = 0.92[/tex]

sin α = 0.92

Answer:

The maximum and minimum temperatures recorded by the thermometer when checked by Wednesday morning are 5°C and -5°C

Step-by-step explanation:

The given parameters are;

A maximum and minimum thermometer is used which records maximum and minimum values as follows;

Initial temperature on Sunday at the time of resetting the thermometer = 4°C

Temperature drop overnight = 5°C, new low = 4 - 5 =  -1°C,

Temperature rise on Monday = 6°C. New high = -1 + 6 = 5°C

Temperature drop on Monday night = 10°C. New low = 5 - 10 = -5°C

Temperature rise on Tuesday = 4°C = New high = 4 + - 5 = -1°C

Temperature drop on Tuesday night = 2°C. New low = -1 - 2 = -3°C

Therefore, the maximum and minimum temperatures recorded by the thermometer when checked by Wednesday morning are 5°C and -5°C.

Answer:

the mode would be 24

Step-by-step explanation:

it is what numbers appears most often

Answer:

A. x + 100x/y

Step-by-step explanation:

Machine A= x hours longer to produce 660 widget than machine B

Machine B produces y% more widget per hour than machine A

let

b = Number of hours it takes Machine B to make 660 widgets.

Time taken for Machine A to make the 660 widgets = x + b.

Rate of Machine B = 660/b

Rate of Machine A = 660 / (x + b).

Machine B produces y% more widgets per hour than Machine A:

660 / (x + b)(1 + y/100) = 660/b

1 / (x + b)(1 + y/100) = 1 / b

Multiply both sides by (x+b)

1 + y/100 = (x + b)/b

1 + y/100 = x/b + 1

Subtract 1 from both sides

y/100 = x/b

Take the inverse of both sides

100/y = b/x

Make b the subject

100x/y = b

b=100x/y

The time taken for Machine A to make the 660 widgets is x + b = x + 100x/y.

Answer is A. x + 100x/y

Answer:

Step-by-step explanation:

I'm assuming you are trying to solve for x. I'm not sure, but that's what I figured out for the answer, so I'm gonna go with that. : )

We are looking for the value of x to make that statement true. It's going to take some trig manipulations, but if you are at this level of precalc, these identities should definitely NOT be new to you. We will begin by squaring both sides of that equation to get:

[tex]9sin^2(x)+3cos^2(x)=3[/tex]

From here we will factor out a 3 to get:

[tex]3(3sin^2x+cos^2x)=3[/tex] and then divide both sides by 3 to get:

[tex]3sin^2x+cos^2x=1[/tex]

Knowing the Pythagorean identity for the trig ratios, we will replace the sin-squared with what it is equal to in terms of cos-squared. If:

[tex]sin^2x+cos^2x=1[/tex], then

[tex]sin^2x=1-cos^2x[/tex]. Making that replacement gives us an equation with only one trig ratio in it, namely, cos:

[tex]3(1-cos^2x)+cos^2x=1[/tex] and distributing:

[tex]3-3cos^2x+cos^2x=1[/tex] which simplifies down to:

[tex]-2cos^2x=-2[/tex]. Divide both sides by -2 to get:

[tex]cos^2x=1[/tex]. When you take the square root of both sides you get:

[tex]cos(x)=1[/tex] and [tex]cos(x)=-1[/tex]. Here is where we will use the unit circle to see where the cos is 1 and where the cos is -1. You didn't give me an interval in which to work, so I am going to use from 0 degrees to 180. Within that interval, the cos is 1 at 0 degrees; within that interval, the cos is -1 at 180.

Now we need to plug those values into the original equation to see if they work. One of them may be extraneous. Plugging in 0 first:

3sin(0) + √3cos(0) = -√3. We need to see if this is true.

The sin of 0 is 0; the cos of 0 is 1, so

0 + (√3)(1) = -√3?

The left side is √3, not -√3, so 0 doesn't work. Let's try 180 now, shall we?

3sin(180) + √3cos(180) = -√3. We need to see if this is true.

The sin of 180 is 0; the cos of 180 is -1, so

0 + (√3)(-1) = -√3?

The left side is -√3 and so is the right side, so

x = 180°

Answer:

The anwser is C) C < 4

......... .

Answer:

8% out of 175 = ( 8 ÷ 100 ) × 175 = 14

175 cm - 14 = 161 cm

...............

Answer:

3 chocolate bars and 2 graham crackers

Step-by-step explanation:

8 times 3 equals 24

12 times 2 equals 24

Answer:

15. 6444.44445

14. 484

Step-by-step explanation:

Answer: I think it would be C

Step-by-step explanation:

Answer:

the correct answer is C because its the only polygon with a caved in feature

Answer:

The correct answer is

Step-by-step explanation:

11 square centimeters.

Hope this helps....

Have a nice day!!!!

Answer:

Q2: -17

Q3: a) -5/2  b) g = -13

Step-by-step explanation:

2w+7 = -9

2w = -9 - 7

w = -16/2

w = -8

---

15 - 4w

= 15 - 4(-8)

= 15 - 32

= -17

----------------------

Q3:

a) 3/4(16m-24) = -48

16m -24 = -48 ÷ 3/4

16m = -64 + 24

16m = -40

m = -5/2

b) -20 = 1/6(36+12g)

-20 = 1/6 × 6(6+2g)

(cross out the 6 from 1/6 and 6)

-20 = 6 + 2g

-20-2g= 6

-2g = 6+20

-2g = 26

g = 26/-2

g = -13

Answer:

7A-42

Step-by-step explanation:

Answer:

0.88175960442

Step-by-step explanation:

The square root of 0.7775 is 0.88175960442

The value of standard deviation will be;

⇒ 0.8803

What is mean by square root of a number?

A square root of a number is a value that multiplied by itself gives the same number.

Given that;

The value of Variance = 0.7775

Now,

Since, The standard deviation is the square root of the variance.

Hence, We can formulate;

The value of standard deviation = √0.7775

                                                 = 0.8803

Thus, The value of standard deviation will be;

⇒ 0.8803

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Answer:

x=2

Step-by-step explanation:

3(x+2) = 12

Divide by 3

3/3(x+2) = 12/3

x+2 = 4

Subtract 2 from each side

x+2-2 = 4-2

x =2

Answer:

The value of x is equal to 2.

Step-by-step explanation:

3(x + 2) = 12

Distribute 3 to (x + 2)

3x + 6 = 12

Subtract 6 from both sides of the equation.

3x = 6

Divide 3 on both sides of the equation.

x = 2

The value of x is 2

Answer:

3 / 19

Step-by-step explanation:

Given the following :

ratio of college graduates with a graduate degree to non-college graduates = 1:8

ratio of college graduates without a graduate degree to non-college graduates is 2:3

If college graduate with a degree = A

College graduate without a degree = B

Non-college graduate = C

College graduate to non college graduate = A:C

College graduate without degree to non college graduate = B:C

A:C = 1:8 - - - (1) ; B:C = 2:3 - - - (2)

Combining the two ratios :

To do so : the proportion of non college graduate should be the same in both ratios

To do this, multiply (1) by 3 and (2) by 8

A:C = 3 : 24

B:C = 16 : 24

combining both, we have :

A:B:C = 3:16:24

If one random college graduate is picked, what is the probability that they hold a graduate degree?

Total proportion of college graduate : (college graduates with degree + college graduates without degree)

A + B = (3 + 16) = 19

Proportion who hold a graduate degree = A = 3

Probability = require outcome / Total possible outcomes

Thus :

P = A / (A +B)

= 3/19

Answer:

son2: 5

son1: 10

Step-by-step explanation:

2x (son1) + x (son2) + 35 (mother) + 3 (years)*3 (people) = 59

3x = 15

x = 5

The age of each boy at present will be 2 years and 3 years.

A linear system is one in which the parameter in the equation has a degree of one. It might have one, two, or even more variables.

Let the age of the sons will be x and y.

A mother who is 35 years old has two sons, one of whom is twice as old as the other. Then the equation will be

x = 2y

In 3 years, the sum of all their ages will be 59 years. Then the equation will be

x + y + x + 1 + y + 1 + x + 2 + y + 2 + 35 = 59

Simplify the equation, we have

3x + 3y + 41 = 59

      6y + 3y = 59 – 41

              9y = 18

                y = 2

Then the value of x will be

x = 2y

x = 2(2)

x = 4

Thus, the age of each boy at present will be 2 years and 3 years.

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The equation with exactly one solution is  3x + 5 = 2x - 6. Option D is correct.

To determine which equation has exactly one solution, we need to solve each equation and see if we end up with a unique value for 'x'.

4x – 4 + 2x = 6x - 4

Combine the x terms on the left side: 6x - 4 = 6x - 4

This equation is an identity and holds true for all values of x. It doesn't have a unique solution.

B. 2(4x + 5) = 8x + 10

Distribute the 2 on the left side: 8x + 10 = 8x + 10

Similar to the previous equation, this equation is also an identity and holds true for all values of x.

It doesn't have a unique solution.

4x - 8 = 4(x - 4)

Distribute the 4 on the right side: 4x - 8 = 4x - 16

Subtract 4x from both sides: -8 = -16

This equation is contradictory and has no solution.

3x + 5 = 2x - 6

Subtract 2x from both sides: x + 5 = -6

Subtract 5 from both sides: x = -11

This equation has a unique solution, x = -11.

So, the equation with exactly one solution is  3x + 5 = 2x - 6. Option D is correct.

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Answer:

Step-by-step explanation:

Amount charges by plumber =  £ 167.00

Call out fee = £ 18.50

Charge excluding the call out fee = 167 - 18.50 = £ 148.50

Total hours worked = 9 hours

Charge per hour = charge excluding the call out fee ÷ total hours

                           = 148.50 ÷ 9

                          = £ 16.50

Answer:

s - t = 10 - -7 = 17

Step-by-step explanation:

I only see

s - t

nothing else is there to evaluate (or calculate).

s - t = 10 - -7 = 17 (as a double "-" always turns into a "+").

you really needed help with that ?

Answer:

= s-t

= 10 - (-7)

= 10 + 7

= 17

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