During the course of solving equations you will hear the word "Undoing" What does this mean?
How do we undo?
For example, take the equation 3x = 12. This equation states that we multiply x by 3 to get and answer of 12. So to undo the multiplication by 3 we divide both sides by three. Another way is to visualise the three moving from the "x" over to the 12 and dividing into it. The animations below give a visual way of thinking about undoing.
Look at the animation on the right. The equation states that "x" is multiplied by 3 to get the answer "a". Visually we can take the three to the other side and divide it.
If a number is multiplied on one side of the equation we can take it across the equal sign and divide it.
If a number is divided on one side of the equation we can take it across the equal sign and multiply it.
If a number is added on one side of the equation we can take it across the equal sign and subtract it.
If a number is subtracted on one side of the equation we can take it across the equal sign and add it.
