A rectangular table has an area of 21 square feet. If the length is 2 feet less than 3 times its width, find the dimensions of the table.

51 DVDs

Step-by-step explanation:

Let the number of DVDs and CDs sold be x each.

Initial

Number of DVDs= 86

Number of CDs= 52

After selling

Number of DVDs= 86 -x

Number of CDs= 52 -x

Given that there are 3 times as many DVDs than CDs left,

86 -x= 3(52 -x)

Expand:

86 -x= 156 -3x

Bring x terms to 1 side, constant to the other:

3x -x= 156 -86

Simplify:

2x= 70

Divide both sides by 2:

x= 35

Amount of DVDs left

= 86 -x

= 86 -35

= 51