Let \(l=length\) be length and \(w=width\)
\(w=2l-3\)
To find the perimeter add all the sides of the rectangle
\(Perimeter=w+w+l+l\)
Replacing \(w=2l-3\)
\((2l-3)+(2l-3)+l+l=51\)
\(6l-6=51\)
add to both sides 6
\(6l=51+6\)
\(6l=57\)
Divide both sides with 6
\(l=57/6 \\ l=9.5\)
\(w=2l-3 \\ w=2(9.5)-3\\ w=19-3\\ w=16\)
