The area of a rectangle is 50 m2 , and the length of the rectangle is 5 m less than three times the width. Find the dimensions of the rectangle.

Question

whats the answer

Answer 1

Hi Ashley,

 

length of the rectangle is 5 m less than three times the width => l = 3w

 

length of the rectangle is 5 m less than 3w  => (3w - 5)

 

Area, A = lw = (3w-5)w = 50

 

3w² -15w = 50

3w² - 15w -50 = 0

 

Can you solve this quadratic equation for w? [-b+/-sqrt(b²-4ac)]/2a

Answer 2

Hi Ashley,

 

Let x = width

 

     3x -5 = length   (5 less than 3 times the width

 

 

so

 

A = l * w

 

A = (3x-5) * x

 

50 = 3x² - 5x

 

0 = 3x² -5x -50

 

now factor

 

0= (3x + 10) (x - 5)

 

now set each factor equal to zero and solve for x 

 

one of the factors wil give us a negative value for x and that can't be the right answer so we will skip that one

 

x - 5 = 0

 

x = 5      ( our width is 5

 

and our length is 3x-5

 

3x - 5 = 10

 

Hope this helps