Question

(2x-1)(4x^2+2x+1) -8(x^3+1)

Answer 1

\(\left(2x-1\right)\left(4x^2+2x+1\right)-8\left(x^3+1\right)\)

\(=8x^3+4x^2+2x-4x^2-2x-1-8x^3-8\)

\(=\left(8x^3-8x^3\right)+\left(4x^2-4x^2\right)+\left(2x-2x\right)+\left(-1-8\right)\)

\(=0+0+0-9\)

\(=-9\)

Answer 2

`=8x^3-1-8x^3-8`

`=-9`

HĐT số 7: `(A-B)(A^2+AB+B^2)=A^3-B^3`