plis kto pomoże ?? dam naj klasa 6 zad 5

5/3 + 1/5 = 25/15 + 3/15 = 28/15 17/7 - 5/8 = 136/56 - 35/56 = 131 / 56 8/4 x 5/7 = 56/28 x 20 / 28 = 36/28 7/3 x 9 / 11 = 21/11