Question

(x²+2x)² +(9x²+18x)+20

Answer 1

(x^2 + 2x)^2 - 9x^2 - 18x + 20 = (x^2 + 2x)^2 - 9(x^2 + 2x) + 20 
Đặt x^2 + 2x = a ta có: 
a^2 - 9a + 20 = (a - 4)(a - 5) 
Thay ngược lại ta có: (x^2 + 2x - 4)(x^2 + 2x - 5)

Answer 2

e) (x2+2x)2+9x2+18x+20=(x2+2x+4)(x2+2x+5)(x2+2x)2+9x2+18x+20=(x2+2x+4)(x2+2x+5)

Answer 3

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

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