Answer:
9 units
Step-by-step explanation:
If you assume the solution is an integer, then you are looking for factors of 27 that differ by 6. You don't have to look far:
27 = 1×27 = 3×9
If the length is 9 units and the width is 3 units, the width is equal to the length minus 6 units.
The length is 9 units.
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Alternate solutions
You can write an equation for the area using L to represent the length. The area is the product of length and width, so is ...
A = LW
27 = L(L-6) = L^2 -6L
You can "complete the square" by adding the square of half the L coefficient:
27 +3^2 = L^2 -6L +3^2
36 = (L -3)^2 . . . . . simplify a bit
6 = L -3 . . . . . . . . . positive square root
9 = L . . . . . . . . . . . . add 3
The length is 9 units.
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You can also put the quadratic equation into standard form:
L^2 -6L -27 = 0
To factor this, you're looking for factors of -27 that have a sum of -6. From above, we know these are -9 and +3. So the factorization is ...
(L -9)(L +3) = 0
The solutions are the values of L that make these factors be zero:
L -9 = 0 ⇒ L = 9
L +3 = 0 ⇒ L = -3
Only the positive solution is useful as a measure of length. The length is 9 units.
