Question

phân tích đa thức thành nhâ tử (x+2y)^2-(x-y)^2

Answer 1

(x + 2y)² - (x - y)²

= (x + 2y - x + y)(x + 2y + x - y)

= 3y(2x + y)

Answer 2

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

\(=\left[\left(x+2y\right)-\left(x-y\right)\right]\left[\left(x+2y\right)+\left(x-y\right)\right]\)

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

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