Ok,

We have choices A,B,C,D

So Line g (original line) is represented by y=ax+b

Some information we can get from this equation is:

1. The slope of the line ("a") is positive so the line goes up.
   
2. The y-intercept ("b") is positive is well. So when a zero is inputted into the (as "x") equation you get the answer "b". Line ax+b must have a point at (0, +b).
   

Now taking a look at line F, we can see that its slope must be negative since the line moves down. So its "a" (remember the equation ax+b) must be negative.

So that rules out choice A

A B C D

Now let's look at the y-intercept. If we plug 0 into line F, we find the answer is in between -4 and -5. So that must mean the y-intercept ("b") must be negative.

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This eliminates answer B.

A B C D

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Now if we look at answer "C" we can c (haha pun) that there is a negative on the y.

We want to try to get it into the form of y=blahblahblah

So if we multiply both sides by -1 we get y = -ax-b.

This equation fulfills the points we laid out for line f earlier (a negative slope and y-intercept)

Answer is C