All you have to do is move the denominator on the other side, by multiplying.
a-10
------- = -9
20
multiply 20 x -9
= -180
then it becomes a-10=-180
+10 +10
a=-170
Seven and seven thousandths.
If I remember My geometry correctly
you add GH AND EF then divide 2
10 full glasses 2/3 left over because 2/3 divided by 1/16 equals 32/3 equals 10 2/3
