You have the following equation:
4( j - 3) = 9 (j + 2)
In order to solve the previous equation for j, you proceed as follow:
4( j - 3) = 9 (j + 2) apply distribution property both sides
4(j)-4(3) = 9(j)+9(2)
4j - 12 = 9j + 18 subtract 9j and sum 12 both sides
4j - 9j = 18 + 12 simplify
-5j = 30 divide by (-5) both sides
j = 30/(-5) = -6
Hence, the solution to the given equation is j = -6