Question

Rút gọn biểu thức :

E=(x-3)³-(x+3)³

F=(x+1)³-(x+1)³+6(x+1)(x-1)

Answer 1

\(\left(x-3\right)^3-\left(x+3\right)^3\)

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

\(=-6\left(\left(x-3\right)^2+\left(x^2-9\right)+\cdot\left(x+3\right)^2\right)\)

Answer 2

(x+1)³-(x+1)³+6(x+1)(x-1)

  = (x+1-x-1)+6.(x²-1)

  = 6(x²-1)