Вправи: 71

71. Спростіть вираз:

1) c2c-9 – 81c-9 = c2- 81c-9 = c-9(c+9)c-9 = c+91 = c + 9;

2) a2(a-6)2 – 36(a-6)2 = a2- 36(a-6)2 = a-6(a+6)a-6(a-6) = a+6a-6;

3) 3x+5x2- 4 – 2x+7x2- 4 = 3x+5- (2x+7)x2- 4 = 3x+5-2x-7x2- 4 = x-2x-2(x+2) = 1x+2;

4) y2y-2 – 4y-4y-2 = y2- (4y-4)y-2 = y2- 4y+4y-2 = (y-2)2y-2 = y-21 = y – 2.