7 Efectuați:
a (x − 3)(x + 2) + (2x + 1)(3x-2)-2x(x+1);
c (x²+x)(x + 1) - x²(2 + x) + (x + 2)(3+x²)-6;
e (3x + 1)(x² + 2x-5)-(x + 2)(2x²-x+3);
b (x-6) (2x + 5) - (x+2)(x+3)+(3-x)(x + 4);
d (x² + 2x) (x + 3) + 2x(x²-x-1)-(3x - 1)(x²-x);
f (x-4) (2x²+x+3)+ (3x-2)(x - 5x² +19).