А) 5 а+2/а² - 3 а+2/а²

б) 6-х/2 х² - 4-х/2 х²

в) 4 х-5/6 х-3 + 7 х-9/6 х-3 - 9 х-13/6 х-3

г) 3 а-5b/a-b + 2a-4b/b-a

1) (5a+2) - (3a+2) / a² = 5a+2-3a-2/a² = 2a/a² = 2/a;

2) (6-x) - (4-x) / 2x² = 6-x-4+x/2x² = 2/2x²=1/x²;

3) (4x-5) + (7x-9) - (9x-13) / 6x-3 = 4x-5+7x-9-9x+13/6x-3 = 2x-1/6x-3 = 2x-1/3 (2x-1) = 1/3;

4) 3a-5b/a-b - 2a-4b/a-b = (3a-5b) - (2a-4b) / a-b = 3a-5b-2a+4b/a-b = a-b/a-b=1