The correct answer is D . A is incorrect because the original expression has numbers next to a parenthesis . Which means that you have to multiply . 5(x+8) + 6(x-3)+10(x+4) 5x + 40 + 6x+ -18 + 10x+40 The answer is not C because it's not positive 18 . It's -18. 6x-18=6x+-18