Answer:
1. {5,-9}
2.{4}
3.{9/2}
Step-by-step explanation:
The equation
can be solved as follows:




Then, the solutions of the equation are
.
Now, if
, we can solve the equation
as follows:




So, the unique solution of this last equation is 
The last equation is
, where
. To solve this equation we can proceed as follows:







But, x=11/4 is not a solution of this equation. So the unique solution is x=9/2.