\(A=3\left(x-1\right)^2-\left(x+1\right)^2+2\left(x-3\right)\left(x+3\right)\)
\(A=3\left(x^2-2x+1\right)-\left(x^2+2x+1\right)+2\left(x^2-9\right)\)
\(A=3x^2-6x+3-x^2-2x-1+2x^2-18\)
\(A=4x^2-8x--16\)
\(B=5x\left(x-7\right)\left(x+7\right)-2\left(2x-1\right)^2\)
\(B=5x\left(x^2-49\right)-2\left(4x^2-4x+1\right)\)
\(B=5x^3-245x-8x^2+8x-2\)
\(B=5x^3-8x^2-253x-2\)
\(C=\left(x^2-2\right)\left(x^2+2\right)-x^2+4\)
\(C=\left(x^2\right)^2-2^2-x^2+4\)
\(C=x^4-4-x^2+4\)
\(C=x^4-x^2\)
\(D=\left(4x-1\right)\left(1+16x^2+4x\right)-\left(4x+1\right)^3\)
\(D=\left(4x-1\right)\left(16x^2+4x+1\right)-\left(64x^3+48x^2+12x+1\right)\)
\(D=64x^3-1-64x^3-48x^2-12x-1\)
\(D=-48x^2-12x-2\)
\(A=3\left(x^2-2x+1\right)-\left(x^2+2x+1\right)+2\left(x^2-3^2\right)\\ =3x^2-6x+3-x^2-2x-1+2x^2-18\\ =4x^2-8x-16\)
\(B=5x\left(x^2-7^2\right)-2\left(4x^2-4x+1\right)\\ =5x^3-245x-8x^2+8x-2\\ =5x^3-8x^2-237x-2\)
\(C=\left(x^4-2^2\right)-x^2+4\\ =x^4-4-x^2+4\\ =x^4-x^2\)
\(D=\left(4x\right)^3-1^3-\left(64x^3+48x^2+12x+1\right)\\ =64x^3-1-64x^3-48x^2-12x-1\\ =-48x^2-12x-2\)