Question

phân tích thành nhân tử:

a. (x^2 + 2x)^2 + 9x^2 + 18x + 20

b. x^2 - 4xy - 2x + 4y^2 + 4y - 35

c. (x+2)(x+4)(x+6)(x+8) = 16

Answer 1

a: \(=\left(x^2+2x\right)^2+9\left(x^2+2x\right)+20\)

\(=\left(x^2+2x+4\right)\left(x^2+2x+5\right)\)

b: \(=\left(x^2-4xy+4y^2\right)-2\left(x-2y\right)-35\)

\(=\left(x-2y\right)^2-2\left(x-2y\right)-35\)

\(=\left(x-2y-7\right)\left(x-2y+5\right)\)

c: Sửa đề: \(\left(x+2\right)\left(x+4\right)\left(x+6\right)\left(x+8\right)+16\)

\(=\left(x^2+10x+16\right)\left(x^2+10x+24\right)+16\)

\(=\left(x^2+10x\right)^2+40\left(x^2+10x\right)+384+16\)

\(=\left(x^2+10x\right)^2+40\left(x^2+10x\right)+400\)

\(=\left(x^2+10x+20\right)^2\)