Answer: 
Step-by-step explanation:
You have the equation
.
Then, to solve for the variable
from the equation you need:
Make the subtraction of the right side of the equation:
(As the denominators are 1 and
, the least common denominator is
)

Multiply
to both sides:

Add
to both sides:

And finally divide both sides by
:

It’s not a function because the domain (the X) is repeating...
X cannot repeat if you want it to be a function
x - 4 = -12
I think x = -8 as if you decrease -8 by 4 it will leave us with the answer of -12
x = -8
Hope this helped,
Jon
3x + 4y = 31
2x - 4y = -6
*The +4 and -4 in the center of the equation cancel out because 4-4 = 0*
3x = 31
2x = -6
------------
*add like terms*
3x + 2x = 5x
31 - 6 = 25
So now you should have this written on your paper ... > 5x = 25
*Divide by 5 on each side*
5x = 25
_ _
5 5
x = 5