Question

rút gọn

a)\(\left(x+3\right)\left(x^2-3x+9\right)-\left(54+x^3\right)\)

Answer 1

\(\left(x+3\right)\left(x^2-3x+9\right)-\left(54+x^3\right)\)

\(=x^3-3x^2+9x+3x^2-9x+27x-54-x^3\)

\(=27x-54\)

Answer 2

\(\left(x+3\right)\left(x^2-3x+9\right)-\left(54+x^3\right)\)

= \(\left(x^3+27\right)-\left(54+x^3\right)\)

=\(x^3+27-54-x^3\)

= -27