Question

This is the one!!!!!!!!!!!

Answer 1

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

Answer 2

Ok!
The answer is a = -170.

First, multiply 20 on both sides.
Next, add the 10 on both sides. This will leave you with a being equal to -170 :)