Respuesta :

Step-by-step explanation:

perimeter = 2(length) + 2(width)

let x represent the width of the rectangle

[tex]30 = 2x + 2(x + 9)[/tex]

[tex]30 = 4x + 18[/tex]

[tex]12 = 4x[/tex]

[tex]x = 3[/tex]

therefore width = 3 cm

length = 3+9

= 12cm