Bài 5:
c: Ta có: \(C=x\left(x^3+x^2-3x-2\right)-\left(x^2-2\right)\left(x^2+x-1\right)\)
\(=x^4+x^3-3x^2-2x-x^4-x^3+x^2+2x^2+2x-2\)
=-2
Bài 5:
a: Ta có: \(A=\left(3x+7\right)\left(2x+3\right)-\left(3x-5\right)\left(2x+11\right)\)
\(=6x^2+9x+14x+21-6x^2-33x+10x+55\)
=76
b: Ta có: \(B=\left(x^2-2\right)\left(x^2+x-1\right)-x\left(x^3+x^2-3x-2\right)\)
\(=x^4+x^3-x^2-2x^2-2x+2-x^4-x^3+3x^2+2x\)
=2