SOLUTION: The length of a rectangle is 6 ft. Greater than its width.the area is 832 sq/ft. Find its dimensions

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Question 931655: The length of a rectangle is 6 ft. Greater than its width.the area is 832 sq/ft. Find its dimensions
Found 2 solutions by Alan3354, Stitch:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
The length of a rectangle is 6 ft. Greater than its width.the area is 832 sq/ft. Find its dimensions
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Try pairs of factors of 832.
Find a pair that differ by 6
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1*832 NG
2*416 NG
etc

Answer by Stitch(470) About Me  (Show Source):
You can put this solution on YOUR website!
Equation 1: A+=+L+%2A+W The area of a rectangle
Equation 2: L+=+W+%2B+6
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We are given A = 832.
Since equation 2 is already solved for L, plug (W+6) into equation 1 for L
Equation 1: A+=+L+%2A+W
832+=+%28W%2B6%29+%2A+W
Multiply the W through.
832+=+W%5E2+%2B+6W
Set the equation equal to zero by subtracting 832 from both sides.
0+=+W%5E2+%2B+6W+-+832
Now we can use the quadratic equation
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation aW%5E2%2BbW%2Bc=0 (in our case 1W%5E2%2B6W%2B-832+=+0) has the following solutons:

W%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%286%29%5E2-4%2A1%2A-832=3364.

Discriminant d=3364 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-6%2B-sqrt%28+3364+%29%29%2F2%5Ca.

W%5B1%5D+=+%28-%286%29%2Bsqrt%28+3364+%29%29%2F2%5C1+=+26
W%5B2%5D+=+%28-%286%29-sqrt%28+3364+%29%29%2F2%5C1+=+-32

Quadratic expression 1W%5E2%2B6W%2B-832 can be factored:
1W%5E2%2B6W%2B-832+=+1%28W-26%29%2A%28W--32%29
Again, the answer is: 26, -32. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B6%2Ax%2B-832+%29

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Since we can only have a positive distance, 26ft is W.
highlight_green%28W+=+26ft%29
Now plug 26 into equation 2 for W
Equation 2: L+=+W+%2B+6
L+=+26+%2B+6
highlight%28L+=+32ft%29