Answer: y = -x - 9
Explanation:
slope intercept is y = mx + b, we can find the slope using the given points
m or slope = (y2 - y1) / (x2 - x1)
lets make (3,-12) be (x1 , y1) and (-9 , 0) be(x2,y2)
m = 0- - 12 / -9 - 3
= 12/-12
m = -1
now y = -1x + b plug in one of the points lets do (-9,0) into this
0 = -1(-9) + b
0 = 9 + b subtract 9 on both sides to find b
-9 = b
so y = -x - 9