The formula of a perimeter of a rectangle:
[tex]P=2(l+w)[/tex]
l - length
w - width
We have
w - width
w + 9 - length
130 cm - perimeter
Substitute:
[tex]2(w+9+w)=130[/tex] divide both sides by 2
[tex]2w+9=65[/tex] subtract 9 from both sides
[tex]2w=56[/tex] divide both sides by 2
[tex]\boxed{w=28}[/tex]
[tex]w+9=28+9\\\\w+9=37[/tex]
