SOLUTION: if the area of a rectangle=84ft^2 find its dimensions area of a rectangle is L*W W=? L=5ft-w

Question 1115764: if the area of a rectangle=84ft^2 find its dimensions
area of a rectangle is L*W
W=?
L=5ft-w
Found 2 solutions by rothauserc, Alan3354:
Answer by rothauserc(4718) (Show Source): You can put this solution on YOUR website!
I think you meant to state the problem this way,
:
width(w) is 5ft less than the length(l)
:
l * (l-5) = 84
:
l^2 -5l = 84
:
l^2 -5l -84 = 0
:
(l-12) * (l+7) = 0
:
l = 12 or l = -7
:
we reject the negative value for l
:
l = 12
:
w = 12 -5 = 7
:
*******************************************************************
dimensions of the rectangle are length = 12 feet and width = 7 feet
*******************************************************************
:
********** stated problem *********
:
(5-w) * w = 84
:
5w -w^2 = 84
:
w^2 -5w +84 = 0
:
the discriminant is
:
square root((-5)^2 -4 * 1 *84) =
:
square root(25 -336) =
:
square root(-311) =
:
an imaginary number involving i(square root(-1)
:
**********************************
this problem has no real solution
**********************************
:

Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
if the area of a rectangle=84ft^2 find its dimensions
area of a rectangle is L*W
W=?
L=5ft-w
------------
L+W = 5
The max area is of a square --> L = W = 2.5
Max area = 6.25 sq ft
84 sq ft is not possible.

RELATED QUESTIONS
The area A of a rectangle is length l times its width w. Express the area of the... (answered by richwmiller)
Find the area of a rectangle if l=15 in., w=2... (answered by misscrt)
For the following problem, I know A = l w, is it l=w+2 and A=60? 60=w+2(w) being the... (answered by stanbon)
I saw this problem in my textbook: A rectangle has a perimeter of 42 miles and an area... (answered by solver91311)
A rectangle has a width of 3X+5, the length is twice this. If the perimeter is 228 find (answered by mananth)
The perimeter of a rectangle is 50 ft. Describe the possible length of a side if the area (answered by Alan3354)
Find the area of a rectangle if it measures L=9 in and... (answered by checkley71)
The area of a rectangle is 49in. Express the perimeter as a function of the width w, and... (answered by chessace)
Question: If the area of a golden rectangle is 6m squared, what are the length and width... (answered by Fombitz)