Question

(x+4x)^2+9x^2-6x(x^2+4x)

Answer 1

\(\left(x+4x\right)^2+9x^2-6x\left(x^2+4x\right)=\left(5x\right)^2+9x^2-6x^3-24x^2=-6x^3+10x^2\)

Answer 2

\(\left(x+4x\right)^2+9x^2-6x\left(x^2+4x\right)\)

\(=25x^2+9x^2-6x^3-24x^2\)

\(=10x^2-6x^3\)