Start by combining the like terms on both sides of the equation. On the left, the like terms are 2x and -x (because both contain an x), and on the right, the like terms are x and x (both contain an x).
Left:
2x-x=x
Right:
x+x=2x
Now, the equation reads: 1+x=-5+2x. You now need to isolate the variable by subtracting x from both sides:
1=-5+x
You can solve this like any other equation:
*Add 5 to both sides*
6=x
The answer is x=6.
Hope this helps!!