−3−34(c−4)=54 ppl pls help

Sanderson is having trouble with his assignment. his shown work is as follows: − 3 7 7 3 = − 3 7 × 7 3 = − 21 21 = −1 however, his answer does not match the answer that his teacher gives him. complete the description of sanderson's mistake. find the correct answer.

With this question, the answer with the red arrow is incorrect!

If f(x) = 5х – 2 and g(x) = 2х + 1, find (f – g)(x).