Question

Rút gọn các biểu thức sau:

\(C=\left(3x+3\right)^3-2\left(x+1\right)^3-\left(5x-1\right)^2\\ D=\left(-2x+3\right)^2-\left(x+1\right)^2+\left(3x-1\right)^2\)

Answer 1

\(C=\left(3x+3\right)^3-2\left(x+1\right)^3-\left(5x-1\right)^2\)

\(C=27x^3+81x^2+81x+27-2x^3-6x^2-6x-2-25x^2+10x-1\)

\(C=25x^3+50x^2+85x+24\)

 

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

\(D=4x^2-12x+9-x^2-2x-1+9x^2-6x+1\)

\(D=12x^2-20x+9\)