Question 353545
let width be x 
length = 3x+1
..
x(3x+1)= 80
3x^2 +x=80
3x^2+x-80=0
3x^2+16 x -15x-80=0
x(3x+16)-5(3x+16)=0
(3x+16)(x-5)=0
So x = 5 the width.
length = 3x+1=  16
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