Multiply the (7/5)x by 2 so you can add it with the (1/10)x
(14/10)x + (1/10)x = (15/10)x
Multiply 9/10 by 4 and 5/8 by 5 so they can interact
(25/40) - (36/40) = -11/40
Multiply both sides by 10/15, the reciprocal of 15/10, so you can get x alone
x = -11/60
