Answer:
[tex]w = 16cm \\ l = 36cm[/tex]
Step-by-step explanation:
[tex]2l + 2w = perimeter \: of \: rectangle[/tex]
Write an equation for the length in terms of w...
[tex]l = 2w + 4cm[/tex]
Then plug the equation for L into the equation for the perimeter...
[tex]2(2w + 4cm) + 2w = 104cm[/tex]
then solve for w...
Multiply the 2 through the parentheses...
[tex]4w + 8cm + 2w = 104cm[/tex]
Add the w terms together and subtract 8cm from both sides...
[tex]6w = 96cm[/tex]
then divide both sides by 6
[tex]w = 16cm[/tex]
plug the dimension for w into the equation for L...
[tex]l = 2(16cm) + 4cm[/tex]
[tex]l = 36cm[/tex]