Question

giúp mình với gấp quá=(((

Answer 1

Bài 4:

b) 

a) Ta có: \(\left(2x-3\right)\left(3x^2-x-1\right)\left(3x-1\right)\)

\(=\left(6x^2-2x-9x+3\right)\left(3x^2-x-1\right)\)

\(=\left(6x^2-11x+3\right)\left(3x^2-x-1\right)\)

\(=18x^4-6x^3-6x^2-33x^3+11x^2+11x+9x^2-3x-3\)

\(=18x^4-39x^3+14x^2+8x-3\)

b) Ta có: \(\left(x^2+2x-3\right)\left(x^2+2x+3\right)\)

\(=\left(x^2+2x\right)^2-9\)

\(=x^4+4x^3+4x^2-9\)