Question 130303
The slope is given by {{{(y[1]-y[2])/(x[1]-x[2])}}}.  So just substitute the coordinates from the two points.  It doesn't really matter, but I'm calling (-3,y) {{{P[1]}}} and (-9,-2) {{{P[2]}}}.


{{{(y-(-2))/((-3)-(-9))}}}


{{{(y+2)/6}}}


But we are given that the slope equals 1, so:


{{{(y+2)/6=1}}}


{{{y+2=6}}}


{{{y=4}}}