SOLUTION: the length of a rectangle is 1 inch less than the width. the area of the rectangle is 21 square inches. what is the length of the rectangle?

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Question 1025334: the length of a rectangle is 1 inch less than the width. the area of the rectangle is 21 square inches. what is the length of the rectangle?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
L=W-1
.
.
L%2AW=21
Substituting,
%28W-1%29W=21
W%5E2-W-21=0
W%5E2-W%2B1%2F4-21=1%2F4
%28W-1%2F2%29%5E2=1%2F4%2B21
%28W-1%2F2%29%5E2=1%2F4%2B84%2F4
%28W-1%2F2%29%5E2=85%2F4
W-1%2F2=0+%2B-+sqrt%2885%29%2F2
W=1%2F2+%2B-+sqrt%2885%29%2F2
Only the positive answer makes sense here.
highlight%28W=%281%2Bsqrt%2885%29%29%2F2%29
L=%281%2Bsqrt%2885%29%29%2F2-1
L=%281%2Bsqrt%2885%29-2%29%2F2
highlight_green%28L=%28sqrt%2885%29-1%29%2F2%29