Question

Rút gọn : (dùng hđt )

 A = (x+2 ) ^ 3+ ( x-2) ^3- 2x( x^2 + 12)

jup' nhé các bn :)) m sẽ tick hết cho các bạn nào tl đug hoặc nhanh nhất :)) :D

Answer 1

\(A=\left(x+2\right)^3+\left(x-2\right)^3-2x\left(x^2+12\right)\)

\(=\left(x+2\right)^3+\left(x-2\right)^3-2x^3-24x\)

\(=x^3+6x^2+12x+8+x^3-6x^2+12x-8-2x^3-24x\)

\(=\left(x^3+x^3-2x^3\right)+\left(6x^2-6x^2\right)+\left(12x+12x-24x\right)+\left(8-8\right)\)

\(=0\)

Answer 2

A=(x+2+x-2)[(x+2)²-(x-2-x+2)+(x-2)²]-2x³-24x

A=2x(x²+4x+4-x+2+x-2+x²-4x+4)-2x³-24x

A=2x(2x²+8)-2x³-24x

A=4x³+16x-2x³-24x

A=2x³-8

A=2(x³-4)