Question

phân tích thành nhân tử :  (x-2x).(x+2x)-x.(x-2).(x+2)

Answer 1

=(x² -4x²)-((x²-2x)(x+2))

=(x²-4x²)-(x³+2x²-2x²-4x)

=x²-4x²-x³+4x

=-x³-3x²+4x=-x(x²+3x-4)

Answer 2

\(\left(x-2x\right)\left(x+2x\right)-x\left(x-2\right)\left(x+2\right)\)

\(=x^2-4x^2-x\left(x^2-4\right)\)

\(=x^2-4x^2-x^3+4x\)

\(=x^2-x^3-4x^2+4x\)

\(=x^2\left(x-1\right)-4x\left(x-1\right)\)

\(=\left(x-1\right)\left(x^2-4x\right)\)

\(=x\left(x-1\right)\left(x-4\right)\)