Question

Manuel builds and sells wooden crates. He made a table to show how much his crates cost.

Answer 1

Answer

D.  y – 85 = 10(x – 8)

Explanation

First we are going to find the slope of the line equation that represents the situation. To do it we are using the slope formula:

$m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$

where

$m$ is the slope of the line

$(x_{1},y_{1})$ are the coordinates of the first point

$(x_{2},y_{2})$ are the coordinates of the second point

From our table we can get the points (2, 25) and (4, 45) so $x_{1}=2$, $y_{1}=25$, $x_{2}=4$, and $y_{2}=45$. Let's replace the values in our formula:

$m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$

$m=\frac{45-25}{4-2}$

$m=\frac{20}{2}$

$m=10$

Now that we have our slope, we are going to use the point slope formula:

$y-y_{1}=m(x-x_{1})$

Since the slope of our line is positive 10, we can rule out answers A and C.

Since the line of answer B has the numbers 4 and 45, we are going to test the point (4, 45) in our point slope formula:

$y-45=10(x-4)$   Nope! Answer B is not correct.

Since the line of answer D has the numbers 8 and 85, we are going to test the point (8, 85) in our point slope formula:

$y-85=10(x-8)$  We got the same line, so D is the correct answer.

Answer 2

C.
y - 65 = -10(x - 6)
is what i say it is but im not for sure, so sry if im wrong.