Question

The length of a rectangle is 5 feet less than its width. If the area of a rectangle is 84 square feet, find its dimensions.

Answer 1

7 x 12

Explanation:

`a=l *w`

`84=l*w\\w=l+5\\`

these equations we know, so we can use them like this

`84=l*(l+5)\\84=l^2 +5l\\`

I then plugged this equation into the desmos calculator to get the answer

`l=7`

we then plug this into a previous equation

`w=l+5\\w=7+5\\w=12`

to get our answer l=7, w=12