y-(3y-7)/7 divided by(20/14)+5/2y
y - (3y-7)/7 = y - 3y/7 + 7/7 = (4y+7)/7
(20/14) + 5/2 y = 10/7 + 5y/2 = (20+35y)/14
(4y+7)/7 / (20+35y)/14
= (4y+7)/7 * 14/(20+35y)
= 2(4y+7)/(20+35y)
Now, if 5/2y means 5/(2y) you need to recalculate. Just keep track of the details.