Question

f(x) = 2x^4 – x^2 – 1
By using the substitution u = x^2, find the horizontal intercepts.

Answer 1

horizontal intercepts mean y = 0:
0 = 2x^4 - x^2 -1
using substitution u = x^2, we get
0 = 2u^2 - u - 1, solve this equation and post your steps.