Вправи: 828

828. Скороти дріб.

a) a-1a-1 = a-1(a-1)(a+1) = 1a+1;

б) x-z x- z = x-z (x-z)(x+ z) = 1x+z;

в) a+ 2a2-2 = a+2 (a-2)(a+2) = 1a-2.

г) a+1a+ a = a+1a(1+a) = 1a;

ґ) a+x aa+ xa = a+ xax(a+x) = 1ax;

д) a+2a+1a-1 = (a+1)2(a-1)(a+1) = a+1a-1.

е) x-6x+9x-9 = (x-3)2(x-3)(x+3) = x-3x+3;

є) (3+1)22+ 3 = 3+23+12+ 3 = 4+232+3 = 2(2+ 3)2+ 3 = 2;

ж) (7-1)27-4 = 7-27+17-4 = 8-277-4 = -2(7-4)7-4 = –2.