(x^2+3x)^2-14x^2-42x+40=0

Question

(x^2+3x)^2-14x^2-42x+40=0

Answer 1

=x^4+9x^2-6x^2-14x^2-42x+40=0

x^4+9x^2-6x^2-14x^2-42x=-40

-53x^11=-40

x=1,325