SOLUTION: the length of a rectangle is 6 centimeters less than four times its width. If the area is 40 square centimeters, find the length and width.

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Question 614333: the length of a rectangle is 6 centimeters less than four times its width. If the area is 40 square centimeters, find the length and width.
Answer by asuar010(338)   (Show Source): You can put this solution on YOUR website!
the width is just w and the length we can describe it as 4w-6 and the area is w*l=40 and if we multiply them we get the equation
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=676 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: 4, -2.5. Here's your graph:

and we take the positive answer of 4 as the width and the lenth is 4(4)-6=10
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