a)
\(2x\left(2-3x\right)+6x^2\\ =4x-6x^2+6x^2\\ =4x\)
b)
\(\left(x-3\right)\left(3+x\right)-x\left(x-2\right)\\ =x^2-9-x^2+2x\\ =x^2-x^2+2x-9\\ =2x-9\)
c)
\(\left(x^2-2x+4\right)\left(x+2\right)-\left(x-2\right)^3-6\left(x-1\right)\left(x+1\right)\)
\(=x^3+8-\left(x^3-6x^2+12x-8\right)-6\left(x^2-1\right)\)
\(=x^3+8-x^3+6x^2-12x+8-6x^2+6\)
\(=x^3-x^3+6x^2-6x^2-12x+8+8+6\)
\(=-12x+22\)
a) \(2x\left(2-3x\right)+6x^2\)
\(=4x-6x^2+6x^2=4x\)
c) \(\left(x-3\right)\left(3+x\right)-x\left(x-2\right)\)
\(=x^2-3^2-x^2+2x=2x-9\)
e) \(\left(x^2-2x+4\right)\left(x+2\right)-\left(x+2\right)^3-6\left(x-1\right)\left(x+1\right)\)
\(=x^3+2^3-\left(x^3-6x^2+12x-8\right)-6\left(x^2-1\right)\)
\(=x^3+8-x^3+6x^2-12x+8-6x^2+6\)
\(=-12x+22\)
