SOLUTION: If the area of a rectangle is 60, and the length of the rectangle is 4 plus the width, what is the equation used to find the width and length of the rectangle?

Algebra ->  Rectangles -> SOLUTION: If the area of a rectangle is 60, and the length of the rectangle is 4 plus the width, what is the equation used to find the width and length of the rectangle?      Log On


   

Question 841603: If the area of a rectangle is 60, and the length of the rectangle is 4 plus the width, what is the equation used to find the width and length of the rectangle?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
x for length, y for width
x=y%2B4 from description.
area, xy=60. Substitute to obtain %28y%2B4%29%2Ay=60
highlight%28y%5E2%2B4y-60=0%29-----this is one of the equations you would use.
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Discriminant=+4%5E2-4%28-60%29=16%2B240=256=16%5E2
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y=%28-4%2B-+16%29%2F2 and you want the POSITIVE result.
highlight%28y=6%29
Note that the quadratic expression is also factorable:
%28y-6%29%28y%2B10%29=0
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You can now find x because you have the value of y.
highlight%28x=10%29