Posted by Anonymous on Tuesday, July 23, 2013 at 4:06pm.
The length of a rectangle is 7 centimeters less than twice its width. Its area is 72 square meters. Find the dimensions of the rectangle.

Algebra world problem  Reiny, Tuesday, July 23, 2013 at 4:43pm
width  x
length  2x7
x(2x7) = 72
2x^2  7x  72 = 0
(x8)(2x+9) = 0
x = 8 or x = 9/2, rejecting the negative width
the rectangle is 8 by 9

Algebra world problem  Chol, Tuesday, July 23, 2013 at 4:59pm
Let l be 2x 7
w = x
A = lw
72 = (2x7)x
72 = 2x^2 7x
2x^2 7x 72 =0
(2x+9)(x8) = 0
x 8 = 0
x = 8
l = 2x7
l = 2(8) 7
l = 167= 9
L = 9 m and w =8 m

Algebra world problem  Ms. Sue, Tuesday, July 23, 2013 at 5:04pm
Aren't the dimensions?
width  x
length  2x0.07

Algebra world problem  Reiny, Tuesday, July 23, 2013 at 11:57pm
good catch Ms Sue.
so
x(2x.07) = 72
2x^2  .07x  72 = 0
x = (.07 ± √576.0049)/4
= 6.017 or a negative
width = 6.017
length = 11.965
check: area = 6.017(11.965) = 71.993 , not bad
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