569 ( а, б) плиз плиз плиз
5/7а+3/14а=13/14а 3/8y+y-1/4y=1/3/8y-1/4y=1 1/8y 13/14*4 2/3=13/14*14/3=13/3=4 1/3 1 1/8*2 2/3=9/8*8/3=9/3=3 13/14*7/13=7/14=1/2 1 1/8*4/9=9/8*4/9=4/8=1/2