SOLUTION: The area of a rectangle is 60 in ^2. The length is 4 inches greater than the width. Find the length. a) 6 in. b) 3 in. c) 4 in. d) 10 in.

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Question 310986: The area of a rectangle is 60 in ^2. The length is 4 inches greater than the width. Find the length.

a) 6 in.
b) 3 in.
c) 4 in.
d) 10 in.
Answer by JBarnum(2146)   (Show Source): You can put this solution on YOUR website!
lw=60
l=4+w
w^2+4w=60
w^2+4w-60
w=6 l=10
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=256 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: 6, -10. Here's your graph: