SOLUTION: A rectangle is drawn so that the width is 4 feet shorter than the length. The area of the rectangle is 12 square feet. Find the length of the rectangle.

Question 861680: A rectangle is drawn so that the width is 4 feet shorter than the length. The area of the rectangle is 12 square feet. Find the length of the rectangle.
Found 2 solutions by ben720, josgarithmetic:
Answer by ben720(159) (Show Source): You can put this solution on YOUR website!

Because the width is 4 ft shorter,

Distribute the l

Subtract 12 from both sides

Use the quadratic formula

OR
OR
OR
Because the length can't be negative, l=6. Because the width is 4 less, it's 2.

The length is 6 feet

Answer by josgarithmetic(39617) (Show Source): You can put this solution on YOUR website!
Common enough to be worth generalizing.
width w, length L.
Width is soe k feet shorter than length, or w=L-k.
Area is given, and may be called A.
The unknown variables are L and w.
(A=12 and k=4).

-
Note that your given values for area and for k may render the quadratic equation in L as factorable. In GENERAL, you cannot rely on factorizability.
General Solution to Quadratic Equation gives for L,

.

You can substitute the values for A and k to compute L.
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