SOLUTION: The height of a box is 7 inches. The length is three inches more than the width. Find the width & length if the volume is 756 cubic inches.

Algebra ->  Volume -> SOLUTION: The height of a box is 7 inches. The length is three inches more than the width. Find the width & length if the volume is 756 cubic inches.      Log On


   



Question 293907: The height of a box is 7 inches. The length is three inches more than the width. Find the width & length if the volume is 756 cubic inches.
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Starting with the formula for the volume of a box:
V+=+L%2AW%2Ah Substitute: V = 756, L = W+3, and h = 7.
756+=+%28W%2B3%29%2AW%2A7 Divide both sides by 7 and simplify..
108+=+W%5E2%2B3W Rearrange into the standard form for a quadratic equation.
W%5E2%2B3W-108 Solve by factoring.
%28W%2B12%29%28W-9%29+=+0 Apply the "zero product" rule.
W%2B12+=+0 or W-9+=+0 so...
W+=+-12 or W+=+9 Discard the negative soltion as width cannot be negative,
highlight%28W+=+9%29inches, and...
L+=+W%2B3
highlight%28L+=+12%29inches.