Question

Complete the equation of the line through (3,-1) and (4,7)

Answer 1

The answer would be Y=8x-25

Answer 2

Firstly , we must find the gradient.

gradient, m = y2 - y1 / x2 - x1

m = 7 - (-1) / 4 - 3
m = 8

a straight line is y=mx+c
thus, we have to find the c which is y-int by subs one of the coordinate to the equation.

y=mx + c
7=8(4) + c
c = -25

thus the equation is y = 8x - 25