the equaiton of a line that passes through the point (x1,y1) and has a slpe of m is
y-y1=m(x-x1)
slope between the points (x1,y1) and (x2,y2) is (y1-y2)/(x1-x2)
given
(-2,-2) ad (1,7)
slope=(-2-7)/(-2-1)=-9/-3=9/3=3
use (1,7)
slope is 3
y-7=3(x-1)
distribute
y-7=3x-3
add 7
y=3x+4
3x-y=-4
