SOLUTION: The Length of a rectangle is 7 feet less than 4 times the width. Find the length and the width of the rectangle if the area is 36 square feet Let w = the width of the rectangle

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Question 831801: The Length of a rectangle is 7 feet less than 4 times the width.
Find the length and the width of the rectangle if the area is 36 square feet
Let w = the width of the rectangle
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Write and expression for the length of the rectangle in terms of w
l =
Since the area of the rectangle is given by the formula A =lw, write an expression for the area A of the rectangle in terms of w.
A =
Set up and solve an appropriate equation and find the width
The width w = (blank) feet. The length l = (blank) feet.
Thank you so much in advance, my son and i cant figure out how to do this problem.
Answer by rothauserc(4718) (Show Source):
You can put this solution on YOUR website!
let l stand for length and w stand for width, then
l = 4w -7
A = (4w -7)w
36 = 4w^2 -7w
rewrite equation
4w^2 -7w -36 = 0
factor the equation
(w-4)(4w+9) = 0
w = 4 or -9/4
we can eliminate w = -9/4 since we are dealing with a positive measure
l = 4*4 -7 = 9
length is 9 feet and width is 4 feet