Вправи: 151

151. Знайдіть суму дробів:

1) 2\43ab + 312ab = 8+312ab = 1112ab;

2) 5y36ac + 4y\49ac = 5y+16y36ac = 21y36ac = 7y12ac;

3) x\74a2b + 3x\214a2b = 7x+6x28a2b = 13x28a2b;

4) 3a\55(a+b) + 6a25(a+b) = 15a+6a25(a+b) = 21a25(a+b);

5) 4y\53(a-c) + 7y15(a-c) = 20y+7y15(a-c) = 27y15(a-c) = 9y5(a-c);

6) 3x\38(a-2b) + 5x\46(a-2b) = 9x+20x24(a-2b) = 29x24(a-2b).