SOLUTION: The area of a rectangular wall hanging in Elizabeth's room is 240 square inches. The width of the hanging is four inches less than twice the length. What are the dimensions of th

Algebra.Com
Question 193383: The area of a rectangular wall hanging in Elizabeth's room is 240 square inches. The width of the hanging is four inches less than twice the length. What are the dimensions of the wall hanging?
Answer by yuendatlo(23)   (Show Source): You can put this solution on YOUR website!
Let width=w, and length=l
w=2l-4
w*l=240
replace w by 2l-4
(2l-4)*l=240
2l^2-4l=240
2l^2-4l-240=0
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation (in our case ) has the following solutons:



For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=1936 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: 12, -10. Here's your graph:

so l can be 12 because the length cannot be negative
replace l with 12
w=2*12-4=24-4=20
Checking:20*12=240
RELATED QUESTIONS

I would like some help on this problem, please. "You are hanging a rectangular mirror in... (answered by stanbon)
Eric is hanging a retangular mirror with the diagonal of 47 inches with angle depression... (answered by FrankM)
Katrina just move into a new house and wants to brighten up the dining room wall by... (answered by jorel1380)
The area of four walls of a room with length 10 inches, width 8 inches and height 6... (answered by richwmiller)
A fabric wall hanging is to fill a space that measures 7 m by 6.5 m. Allowing for 0.1 m... (answered by stanbon,josmiceli)
A fabric wall hanging is to fill a space that measures 5 m by 6.5 m. Allowing for 0.1 m... (answered by Boreal)
Quilt Dimensions. Michelle is making a quilt for a wall hanging at the entrance of a... (answered by josgarithmetic,ikleyn)
A container for a hanging plant is a half sphere with a diameter of 9 inches. About how... (answered by ikleyn)
1. A bell rope, passing through the ceiling above, just barely reaches the belfry floor.... (answered by jim_thompson5910)