To solve 9(2 + x) = 10(7 + x), we need to first evaluate the multiplication and parenthesis on each side of the equation, then get x on one side and all the numbers on the other, and finally solve. Since we can't simplify the parenthesis, we do the multiplication.
18 + 9x = 70 + 10x
18 = 70 + x
x = -52