a) -x^2+3x+4-2+x+3x^2=2x^2+4x+2=2(x^2+2x+1)=2(x+1)^2
2*(3+1)^2=2*4^2=2*16=32
b) (x^3-4x+2)-(x^2-3x-1)-(x^3-2x^2+x) =x^3-4x+2-x^2+3x+1-x^3+2x^2-x=x^2-2x+3
2^2-2*2+3=4-4+3=3
c) 2a-3b-4a-2b+7a-4b=5a-5b=5(a-b)
5(-3\frac{1}{2}-1\frac{1}{3})=5(-3\frac{3}{6}-1\frac{2}{6})=5(-4\frac{5}{6})=\\
5*(-\frac{29}{6})=-\frac{145}{6}=-24\frac{1}{6}
d) 7a-4b+3-5a+3b-1=2a-b+2
2*4,5+3,3+2=9+3,3+2=14,3