You can put this solution on YOUR website! You need to rearrange the formula so that w is on its own on one side of the equals sign. Remember when dealing with equations whatever you do to one side you must do to the other to keep them in balance (keep them equal).
So to start you off notice how we have taken away 21 from both sides of the equation. This simplifies to .
Can you work out the last stage? Clue you need to move the 2 from the right side to the left side. You need to do the opposite of multiplication.
Let me know how you get on.
You can put this solution on YOUR website! if the perimeter of a rectangle is expressed by the formula p=21+2w, the side w can be found by the formula?
Subtract 2*l from both sides of the equation:
2*w = p - 2*l
Divide both sides by 2:
(2*w)/2 = p/2 - (2*l)/2
w = p/2 - l
(