Question

Rút gọn biểu thức:

(x-1)³-(x³-3x²-1)

Giúp mình vs!!

Answer 1

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

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

=\(3x\)

Tick cho mk nha

Answer 2

Chúc bn hok tốt

Answer 3

(x-1)³-(x³-3x²-1)

=x³-3x²+3x-1-(x³-3x²-1)

= x³-3x²+3x-1-x³+3x²+1

= 3x

Answer 4

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

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

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

\(=3x^2\)