Question

solve 2x^4-5x^2+3 take x^2=y

Answer 1

= 2x^4-5x^2+3
= 2(x^2)^2-5(x^2)+3
= 2y^2-5y+3
= 2y^2-(3y+2y)+3
= 2y^2-3y-2y+3
= y(2y-3)-1(2y-3)
= (2y-3) (y-1)