Find the critical points, A and B, of the following polynomial (with A<B). f(x)=6x^3−63x^2+4

Question

A=

B=

Please help!!!!

Answer 1

f'(x) = 18x² - 126x = 18x(x-7)

A = 0

B= 7

Note: looking at the sign of the first derivative in (-∞, 0) (+), (0, 7) (-), and (7, ∞)(+), A is a relative maximum, and B is a relative minimum.