SOLUTION: Please help me solve this question. I dont even know where to start. Thank you for your time and help the area of a rectangular wall of a barn is 120 sq ft. its length is 8ft

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Question 495698: Please help me solve this question. I dont even know where to start.
Thank you for your time and help

the area of a rectangular wall of a barn is 120 sq ft. its length is 8ft longer than twice its width. find the length an width of the wall of the barn.
Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
Area of a rectangle = Length * Width
A+=+area
A+=+120 (given)
.
L+=+length
W+=+width
.
Length is 8 ft greater than twice the width. (given)
L+=+2W+%2B+8%0D%0A.%0D%0AWhat+are+the+length+and+width%3F%0D%0A.%0D%0A%7B%7B%7BL%2AW+=+A
L%2AW+=+120
Substitute for L
%282W%2B8%29%2AW+=+120
Multiply
2W%5E2+%2B+8W+=+120
Subtract 120 from both sides
2W%5E2+%2B+8W+-+120+=+0
Divide by 2 to eliminate the coefficient on W^2
W%5E2+%2B+4W+-+60+=+0
Factor
%28W+%2B10%29%28W+-6%29+=+0
So the width is either -10 or 6.
A negative width is nonsense, so we decide:
W+=+6
.
Substitute for W
L%2A6+=+120
Divide both sides by 6
L+=+20
.
ALWAYS check your work.
In this case, you cannot use the area to check because you used it to solve for L.
Looking back you can find:
L+=+2W+%2B+8
2W+%2B+8+=+2%286%29+%2B+8
2W+%2B+8+=+20
Correct.
.
Answer:
Length = 20 ft.
Width = 6 ft.
.
Done