The length of a rectangle is two feet less than three times width of the rectangle . The area of the reactangle is 65ft. ?
a.) How would you represent the dimensionof the rectangle ?
b.) What equation represent the area of rectangle ?
c.) how will you find the dimension of the rectangle ?
d.)What are dimension of the rectangle?


Sagot :

a.) w=width
     L=length
     L=3w-2

b,) 65=(3w-2)(w)
c.) 3w²-2w-65=0      find the roots,
     factor out the equation:    (3w+13)(w-5)=0
              getting the roots:    3w+13=0         w= -13÷3 = -4.3333333
                                           w-5=0              w=5   (use transposition)

   you obtained two values for the width w, but since there is no negative value for dimension, w=5, must be the correct answer.

d.)  w=5 ft
      since L=3w-2.. then L=3(5)-2   so L=13 ft.

to check: 65=(3w-2)(w)
               65=(3(5)-2)(5)
               65=(13×5)
               65=65