Negative StartFraction 9 Over 15 EndFraction y + StartFraction 3 Over 21 EndFraction = StartFraction 5 Over 15 EndFraction y minus StartFraction 14 Over 21 EndFraction
9/15y + 3/21 = 5/15 y - 14/21. Adding 14/21 to both sides we then get 9/15y + 17/21 = 5/15y. Subtracting 5/15y from both sides, we get 4/15y + 17/21 = 0.
Then we get 4/15y = -17/21. Dividing by 4/15 gets us -17/21 * 4/15 = -68/315 = y.