Question

rút gọn A,B,C

A=(3x+7)(2x+3)-(3x-5)(2x+11)

B=(x²-2)(x²+x-1)-x(x³+x²-3x-2)

C=x(x³+x²-3x-2)-(x²-2)(x²+x-1)

Answer 1

\(A=6x^2+23x+21-\left(6x^2+23x-55\right)=76\\ B=x^4+x^3-x^2-2x^2-2x+2-x^4-x^3+3x^2+2x\\ =2\\ C=x^4+x^3-3x^2-2x-\left(x^4+x^3-x^2-2x^2-2x+2\right)\\ =-2\)