Question

What is the equation of the line, in point-slope form, that passes through the points (-1, 7) and (-2, 3)? A. y + 7 = -4(x - 1) B. y - 7 = -4(x + 1) C. y + 7 = 4(x - 1) D. y - 7 = 4(x + 1)

Answer 1

In general point-point form, the equation for the line through (a,b) and (c,d) is

`(c-a)(y-b) = (d-b)(x-a)`

Here we have (a,b)=(-1,7) and (c,d)=(-2,3)

`(-2 - -1) (y - 7) = (3 - 7)(x - -1)`

`-1(y - 7) = -4(x+1)`

`y - 7 = 4 (x+1)`

Answer: Choice D