Answer
x=26
Work Step by Step
The distributive property allows us to distribute anything multiplied by something inside of the parenthesis to whatever is inside of the parenthesis. Thus, we distribute the 8 to everything inside of the first set of parenthesis and the 9 to everything inside of the second set of parenthesis, giving us the equation 8x+8=9x-18. We now simplify:
$8=x-18 \\\\ x=26$