Question

What is the point-slope form of a line with slope -3 that contains the point (10, -1)?

A.y + 1 = 3(x - 10)
B.x + 1 = -3(y - 10)
C.y + 1 = -3(x - 10)
D.y + 1 = 3(x + 10)

Answer 1

When in point-slope form, the number next to the y and the x by themselves will be the opposite of what they would actually be as coordinates. This means that the y-coordinate, -1, will show up as y+1. This eliminates A and B out of the choices.

The slope is -3, which will be the number outside of the parentheses, which is what we see in C’s answer or -3(x-10).

Therefore, the answer is C: y+1 = -3(x-10).