Hello,
The answer is x= y-13 / 2 ( everything after the x= is a fraction)
How to solve;
Start by subtracting 13 from both sides of y=2x+13, we do this to get the x on 1 side
So now we have y-13=2x
Next divide both sides by 2, we do this to get x by it self.
y-13/2=x
Now we flip the problem and there you have it!
Edit: The x does not have a Pos or neg value, The only way to know what x is, is to solve for x.