A rectangle solar panel has a length that is 12 inches shorter than 4 times it's width. If the perimeter of the panel is 196 inches, what are the dimensions of the panel?

let length =l & width=w

given that l= 4w-12

and also 2(l+w)=196 =>(l+w)=98

solving we get:

4w-12+w=98 =>5w=86 =>w=86/5 = 17.2inches

and l= 98-17.2 = 80.8inches