Calculaţi: a) 7x-2-[-x-(-6x + 2)]; c)x-2-{x-3-[5x-4-(6x-2)]); b)x+5-[3x-6-(2x-10)]; d) 9-{2x-[x-(1-x)+ (2x-1)]}. 174 ci c=426. D OL