Answer:
\(\left(2x+1\right)^2+\left(2x-1\right)^2-2\left(1+2x\right)\left(2x-1\right)\)
\(=(4x^2+4x+1)+(4x^2-4x+1)-2(4x^2-1)\)
\(=4x^2+4x+1+4x^2-4x+1-8x^2+2\)
\(=(4x^2+4x^2-8x^2)+(4x-4x)+(1+1+2)\)
\(=4\)
\((x-1)^3-(x+2)(x^2-2x+4)+3(x-1)(x+1)\)
\(=(x^3-3x^2+3x-1)-(x^3+8)+3(x^2-1)\)
\(=x^3-3x^2+3x-1-x^3-8+3x^2-3\)
\(=(x^3-x^3)+(-3x^2+3x^2)+3x+(-1-8-3)\)
\(=3x-12\)