Word Prob find Length

[wallee]

A gym has a wall with a length that is 6 feet more than three times the height. If a can of paint that covers 1080 square feet is needed to paint the wall, what is the lenght of the wall?

Do I use the formula A=LW because I was thrown off with the height and length. Is there another formula to use?Please help.

 

[masters]

Let h = height of wall
Let 3h + 6 be the length of the wall

Yes, you will use A = LW

1080 = h(3h + 6)

1080 = 3h[sup:7wshtc6s]2[/sup:7wshtc6s] + 6h

Set to 0:

3h[sup:7wshtc6s]2[/sup:7wshtc6s] + 6h - 1080 = 0

Divide all terms by 3:

h[sup:7wshtc6s]2[/sup:7wshtc6s] + 2h - 360 = 0
Now, factor or use the quadratic formula to solve for h.