Class Room Notes

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.