Question

rút gọn biểu thức

(x+1)^3+(x-1)^3+x^3-3x(x+1)(x-1)

Answer 1

\((x+1)^3+\left(x-1\right)^3+x^3-3x\left(x+1\right)\left(x-1\right)\)

\(=x^3+3x^21+3x1^2+x^3-3x^21+3x1^2-1^3-3x\left(x^2-1^2\right)\)

\(=x^3+3x^2+3x+x^3-3x^2+3x-1-3x^3+3x\)

\(=-x^3+9x-1\)

Answer 2