\(a,=4x^2+4x+1-\left(4x^2+3x-4x-3\right)\\ =4x^2+4x+1-4x^2+x+3\\ =5x+4\\ --------------\\ b,=x^3+3x^2+3x+1-x^3-8-3\left(x^2-4\right)\\ =3x^2+3x-7-3x^2+12\\ =3x+5\\ ------------\\ c,=\left[\left(x+3y\right)-\left(3y+2x\right)\right]^2\\ =\left(x+3y-3y-2x\right)^2\\ =\left(-x\right)^2\\ =x^2\)


