The length of a rectangular pizza is 4 in less than twice it's width. The area of the pizza is 160 in ^2. Find the dimensions of the pizza.

Question

I need help on this problem. 

Answer 1

Width = x

Length = 2x-4

Area = x(2x-4) = 160

2x^² -4x -160 =0

x² - 2x -80 = 0

(x -10)(x + 8) =0

x = 10, x = -8

Dimensions of pizza are :

Length =16 inches, width = 10 inches.

 

Answer 2

Let width = x

Let length = 2x - 4

Area = 160 in²

 

width × length = area

 

x(2x - 4) = 160

2x² - 4x = 160

2x² - 4x - 160 = 0

2(x² - 2x - 80) = 0

2(x -10)(x + 8) = 0

 

x = 10     and    x = -8

 

We take the positive value of x.  x = 10.  Substitute this value into the dimensions.

 

width = 10 in

length = 2(10) - 4 = 20 - 4 = 16 in

 

 

To check:

 

10 in  x  16 in = 160 in²

 

    160 in²       =  160 in²