m=(10-5)/(2+3)=5/5=1. Since the slope is 1 and slope-intercept form is y=mx+b, pick one of the ordered pairs given and input for x and y.
5=1(-3)+b. add 3 to both sides to get b=8. The equation is now y=1x+8 (you don't have to put the 1 there but you do you).