Question

Rút gọn biểu thức sau:

Q=\(\left(x+2\right)\left(x^2-2x+4\right)-x\left(x-2\right)\left(x+2\right)+2x\)

Answer 1

\(Q=\left(x+2\right)\left(x^2-2x+4\right)-x\left(2-x\right)\left(x+2\right)+2x\)

\(Q=\left(x+2\right)\left(x^2-2x+4\right)-\left(x^2-2x\right)\left(x+2\right)+2x\)

\(Q=\left(x+2\right)\left[\left(x^2-2x+4\right)-\left(x^2-2x\right)\right]+2x\)

\(Q=\left(x+2\right)\left(x^2-2x+4-x^2+2x\right)+2x\)

\(Q=4\left(x+2\right)+2x\)

\(Q=4x+8+2x\)

\(Q=6x+8\)

Answer 2

Q= (x + 2)(x² - 2x + 4) - x(x - 2)(x + 2) + 2x

= x³ + 8 - x(x² - 4) + 2x

= x³ + 8 - x³ + 4x + 2x

= 6x + 8

Answer 3

Q= (x + 2) (x² - 2x +4) - x(x - 2) (x + 2) + 2x

= x³ + 8 -x(x² - 4 ) + 2x

= x³ + 8 - x³ + 4x + 2x

= 6x + 8