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 +

Click here to see ALL problems on Quadratic Equations

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(52781) (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) (Show Source):
You can put this solution on YOUR website!
Let's call the width, x, and length y.
.
.
Area,
1.
.
.
Perimeter,

2.
From eq. 1,

Substituting into eq. 2,