
Here's an example (which I'll walk you through):
2x + 5 = -1 - x
This has variables on both sides (because there's an x on the left side of the equals sign, and on the right side).
And the solution is also -3. Here's how:
2x + 5 = -1 - x
First, I'll move the x on the right side to the left by adding x to both sides:
2x + 5 + x = -1 - x + x
This cancels out the -x on the right and adds another x to the 2x on the left:
3x + 5 = -1
Now to isolate the 3x, I'll subtract 5 from both sides:
3x + 5 - 5 = -1 - 5
This cancels out the 5 on the left side, and subtracts 5 from the -1 on the right:
3x = -6
Now I'll divide both sides by 3 to get x on its own and find my solution:
3x ÷ 3 = -6 ÷ 3
This cancels out the 3 multiplying the x on the left, and it divides the -6 by 3.
x = -2
And there's your solution :)