1) 7/10 + x = 9/10
Subtract 7/10 from both sides:
x = 9/10 - 7/10
x = 2/10
x = 1/5

2) 29/32 - x = 15/32
Subtract 29/32 from both sides:
-x = 15/32 - 29/32
-x = -14/32
x = 14/32
x = 7/16