the only part im confused about is if i derive y = 6u^2-11 first, then substitute u with 3x^2 +2. or if i substitute u with 3x^2 +2, then expand/simplify, then derivate the entire question. i got two answers. using the first method f'(2) = 2016 and the second method f'(2) = 144 which method is right? or am i just completely wrong.