Question

1.Phân tích đa thức thành nhân tử

a,(2x+1)^2-(x-1)^2

b, 9.(x+5)^2-(x-7)^2

c, x^2-6xy+9y^2

Answer 1

https://i.imgur.com/k7YvpR9.jpg

Answer 2

a) \(\left(2x+1\right)^2-\left(x-1\right)^2\)

\(=\left(2x+1+x-1\right)\left(2x+1-x+1\right)\)

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

b) \(9\left(x+5\right)^2-\left(x-7\right)^2\)

\(=\left[3\left(x+5\right)\right]^2-\left(x-7\right)^2\)

\(=\left(3x+15\right)^2-\left(x-7\right)^2\)

\(=\left(3x+15-x+7\right)\left(3x+15+x-7\right)\)

\(=\left(2x+22\right)\left(4x+8\right)\)

c) \(x^2-6xy+9y^2\)

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

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