Answer:

Step-by-step explanation:
defition of slope(m) of a line:

A=(-1,-5)=(Xa,Ya) then Xa= -1 and Ya= -5
B=(3,-3)=(Xb,Yb) then Xb=3 and Yb= -3

Basically you do fractions side by side. so, 6/3=15/h and then cross multiply to get your answer so that would give you 3h=80, then divide 80÷3