To solve a two step problem you need to decide what operation was done last. Then undo that operation by doing the oposite of that operation.
For example: 3x - 5 = 12
Subtracting was the last operation done, so undo the subtraction operation by adding 5 to both sides of the equation.
3x - 5 + 5 = 12 + 5
The fives cancels each other on the left side of equations
3x = 17
Now the last operation done to the x is multiplication, therefore you need to undo the multiplication by dividing both sides by 3.
3x÷ 3 = 17÷ 3
The threes will cancel each other out leaving the variable by itself. You are aloud to leave tha answer in fraction form.
x = 17/3
Remember that what you do to one side of the equation you have to do to the other side of the equations.