Question

What is the equation of the line, in point-slope form, that passes through the points (-3, -1) and (-6, 8)?

A. y + 8 = -3(x - 6)
B. y - 8 = -3(x + 6)
C. y + 8 = 3(x - 6)
D. y - 8 = 3(x + 6)

Answer 1

B. y - 8 = -3(x + 6)

Explanation:

The point-slope form of an equation of a line:

`y-y_1=m(x-x_1)`

m - slope

(x₁, y₁) - point

The formula of a slope:

`m=(y_2-y_1)/(x_2-x_1)`

We have the points (-3, -1) and (-6, 8). Substitute:

`m=(8-(-1))/(-6-(-3))=(9)/(-3)=-3\\\\y-8=-3(x-(-6))\\\\y-8=-3(x+6)`