Question 1013041
3(-7+r)=-36
Use the distributive property.

1) 3*-7=-21 
3*r=3r
-21+3r= -36
2) Add 21 to both sides.
-21+21=0 (it's canceled out) -36+21=-15

Now, we have 3r=-15

3) Divide by the number in front of the variable 
3r=-15 
3r/3=r= -15/3=-5

4) r=-5