Use the arithmetic operations to get the variable x on one side of the equation and everything else on the opposite side.
If something is being is being done to a variable, we undo that operation by using the inverse of that operation.
For example, if 10 is being added to x, we use the inverse of addition or subtraction.
18 - 7x = -20.5
We variable x is being multiplied by 7 and is subtracting 18. We need to undo all those operations.
18 - 7x = -20.5
-7x = -38.5
Now the variable is only being multiplied by -7. Reverse the operation.
-7x = -38.5
x = 5.5
So, x is equal to 5.5.
