How to find the critical points of a function.

If f(x)= 3x+6 which of the following is the inverse of f(x)

What is the range of the function? f(x)=-2|x+1|? a. all real numbers. b. all real numbers less than or equal to 0. c. all real numbers less than or equal to 1. d. all real numbers greater than or equal to 1

Factor and solve to find roots x squared -x - 90 =0