Question

What is the answer to this question?

Answer 1

C. y = -x + 68

Explanation:

First, remember that slope-intercept form is y = mx + b, where m = slope, b = y-intercept.

We know that the slope is negative. Unfortunately, all the answers have negative slopes, so we can't rule anything out.

Let's look at the y-intercept. It looks like it's around 60, a little higher; 68 and 65 are both good options. It's clearly not 55 or 100, so eliminate choices D and B.

Now let's look at the slopes - it looks like the slope is closer to than 2x. Check out the attached graph - pick points at random and check which graph seems to match them most often!

Answer 2

Answer: C.

Explanation:

To find this, you can take two coordinates that fit the data roughly and find an equation from them.

Mine are (8, 60) and (16, 50).

To find the slope, use
`(y2-y1)/(x2-x1)`:

`(60-50)/(8-16)` is simplified to 10/-8, or 5/-4 (-1.25x).

Next, you can use the slope to find the y-intercept.

Multiply 8 * -1.25 to get -10. To make the y-coordinate equal 60 as it does in the graph, you must add 70 to the equation. It should look like this:

`y = -1.25x + 70`

This aligns very similarly to option C in both slope and y-intercept, so that is likely the correct answer.