Відповіді до вправ § 1 - § 12: 4.20

4.20 Спростіть вираз:

1) 2a + 3a-1 = 2a-1+ 3aa(a-1) = 2a-2+3aa(a-1) = 5a-2a(a-1);

2) ca-c – ca = ac-c(a-c)a(a-c) = ac-ac+ c2a(a-c) = c2a(a-c);

3) 3x+y + 2x-y = 3x-y+ 2(x+y)x+y(x-y) = 3x-3y+2x+2yx+y(x-y) = 5x-yx2- y2;

4) xx-1 + 2x-2 = xx-2+ 2(x-1)x-1(x-2) = x2- 2x+2x-2x-1(x-2) = x2- 2x2- 3x+2;

5) a+1a – aa-1 = a2- 1- a2a(a-1) = -1a(a-1) = 1a- a2;

6) a2a-1 – a2a+1 = 2a2+ a-2a2+ a2a-1(2a+1) = 2a4a2- 1.