Answer:
-13+x or x-13
Step-by-step explanation:
If you call this number y, then y=-13+x or x-13. Hope this helps!
EXPLANATION
Replacing the given functions into the following:


Removing the parentheses and simplifying:

Simplifying like terms:

Hence,
First step is to get variables on one side and constants on the other so that we can combine like terms. To do so, subtract 5x from both sides and subtract 6 from both sides. This gives you:
8x - 5x = 9 - 6
Now combine like terms:
3x = 3
Divide by 3 to isolate the variable x.
x = 1