Answer:
[tex]f(W)=W^{2} +20W[/tex]
Step-by-step explanation:
we know that
The area of a rectangle is equal to
[tex]A=LW[/tex] -----> equation A
we have
[tex]L=W+20[/tex] -----> equation B
substitute the equation B in equation A
[tex]A=(W+20)W[/tex]
Rewrite as a function
[tex]f(W)=(W+20)W[/tex]
[tex]f(W)=W^{2} +20W[/tex]
