Question

factor x^4-20x^2+64

Answer 1

y = x^2

y^2 - 20y + 64
y^2-4y-16y+64
y(y-4)-16(y-4)
(y-4)(y-16)
(x^2 -4)(x^2-16)
(x-2)(x+2)(x-4)(x+4)

Answer 2

Good luck understanding those steps