Question

Rút gọn biểu thức sau:

a)x(x-1)(x+1)-(x+1)(x^2-x+1)

b)3x^2(x+1)(x-1)-(x^2-1)(x^4+x^2+1)+(x^2-1)^3

Answer 1

a.\(x\left(x-1\right)\left(x+1\right)-\left(x+1\right)\left(x^2-x+1\right)\)

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

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

\(=-x-1\)

b.\(3x^2\left(x+1\right)\left(x-1\right)-\left(x^2-1\right)\left(x^4+x^2+1\right)+\left(x^2-1\right)^3\)

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

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

Chắc là vậy!

Answer 2

a) \(x\left(x-1\right)\left(x+1\right)-\left(x+1\right)\left(x^2-x+1\right)\)

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

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

\(=-x+1\)