SOLUTION: The perimeter of rectangle ABCD is 42 cm and the area is 80 cm^2. Which equation can be used to find the dimensions of the rectangle? (Hint: Set up a system of equations). xy +

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Question 1024336: The perimeter of rectangle ABCD is 42 cm and the area is 80 cm^2. Which equation can be used to find the dimensions of the rectangle? (Hint: Set up a system of equations).
xy + 2x + 2y = (42)(80)
x2 + 80x - 42 = 0
x2 - 42x + 80 = 0
x2 - 21x + 80 = 0

Found 2 solutions by ikleyn, Fombitz:
Answer by ikleyn(52778) About Me  (Show Source):
You can put this solution on YOUR website!
.
The perimeter of rectangle ABCD is 42 cm and the area is 80 cm^2. Which equation can be used to find the dimensions of the rectangle? (Hint: Set up a system of equations).

xy + 2x + 2y = (42)(80)
x2 + 80x - 42 = 0
x2 - 42x + 80 = 0
x2 - 21x + 80 = 0
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Answer. The last equation.


Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let's call the width, x, and length y.
.
.
Area,
1.A=L%2AW=xy=80
.
.
Perimeter,
P=2%28L%2BW%29=2%28x%2By%29=42
2.x%2By=21
From eq. 1,
y=80%2Fx
Substituting into eq. 2,
x%2B80%2Fx=21
x%5E2%2B80=21x
x%5E2-21x%2B80=0