Question

Phân tích thành nhân tử

\(\left(x+y\right)^2-9x^2\)

Answer 1

\(\left(x+y\right)^2-9x^2\)

\(=\left(x+y\right)^2-\left(3x\right)^2\)

\(=\left(x+y-3x\right)\left(x+y+3x\right)\)

\(=\left(y-2x\right)\left(4x+y\right)\)

Answer 2

\(\left(x+y\right)^2-9x^2\)

\(=\left(x+y\right)^2-\left(3x\right)^2\)

\(=\left(x+y+3x\right)\left(x+y-3x\right)\)

\(=\left(4x+y\right)\left(y-2x\right)\)