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3 years ago

Help again, right answers only please :)

Mathematics

1 answer:

Digiron [165]3 years ago

8 0

The first question is c
the second is d

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Persons taking a 30-hour review course to prepare for a standardized exam average a score of 620 on that exam. Persons taking a

Alina [70]

Given:

30-hour review course average a score of 620 on that exam.

70-hour review course average a score of 749.

To find:

The linear equation which fits this data, and use this equation to predict an average score for persons taking a 57-hour review course.

Solution:

Let x be the number of hours of review course and y be the average score on that exam.

30-hour review course average a score of 620 on that exam. So, the linear function passes through the point (30,620).

70-hour review course average a score of 749. So, the linear function passes through the point (70,749).

The linear function passes through the points (30,620) and (70,749). So, the linear equation is:

$y-y_1=\dfrac{y_2-y_1}{x_2-x_1}(x-x_1)$

$y-620=\dfrac{749-620}{70-30}(x-30)$

$y-620=\dfrac{129}{40}(x-30)$

$y-620=\dfrac{129}{40}(x)-\dfrac{129}{40}(30)$

$y-620=\dfrac{129}{40}(x)-\dfrac{387}{4}$

Adding 620 on both sides, we get

$y=\dfrac{129}{40}x-\dfrac{387}{4}+620$

$y=\dfrac{129}{40}x+\dfrac{2480-387}{4}$

$y=\dfrac{129}{40}x+\dfrac{2093}{4}$

We need to find the y-value for $x=57$ .

$y=\dfrac{129}{40}(57)+\dfrac{2093}{4}$

$y=183.825+523.25$

$y=707.075$

$y\approx 707.1$

Therefore, the required linear equation for the given situation is $y=\dfrac{129}{40}x+\dfrac{2093}{4}$ and the average score for persons taking a 57-hour review course is 707.1.

4 0

3 years ago

All of the angles are exterior angles EXCEPT:

MaRussiya [10]

Answer:

Step-by-step explanation:

XYZ

The first one

I hope I helped you.

7 0

3 years ago

Yes, it is correct

alexgriva [62]

Answer:In Heather's solution to the problem, she wrote and solved an equation.

Her work is:

Step 1: 1.08(x +9.01 +0.98 +5.01) = 21.87

Solving like terms

1.08(x+15}=21.87

dividing both side by 1.08

we get

x+15=21.87/1.08

x+15=20.25

subtracting both side by 13.9198

x=20.25-15

x=5.25

According to correction

;

Option 1st

yes,it is correct

7 0

3 years ago

Permutations: 5!·4! is equivalent to what (5!)(4!)^2, (5)(4!)^2 or 20! ?

solniwko [45]

Answer:

5!*4! is equivalent to 5*(4!)^2

Step-by-step explanation:

5!*4! = 2880

5*(4!)^2 = 2880

4 0

3 years ago

For the function F defined by F(x) = x2 – 2x + 4, find F(b+3).

Ivanshal [37]

Answer:

$\displaystyle F(b + 3) = b^2 + 4b + 7$

Step-by-step explanation:

We are given the function:

$\displaystlye F(x) = x^2 - 2x + 4$

And we want to find F(b + 3).

We can substitute:

$\displaystyle F(b + 3) = (b + 3)^2 - 2(b+3) + 4$

Expand:

$\displaystyle = (b^2 + 6b + 9) + (-2b -6) + 4$

Rearrange:

$\displaystyle = (b^2) + (6b-2b) + (9 - 6 + 4)$

Combine like terms. Hence:

$\displaystyle = b^2 +4b + 7$

In conclusion:

$\displaystyle F(b + 3) = b^2 + 4b + 7$

6 0

3 years ago