Answer:
[tex]A(w) = (40 - w) * w[/tex]
Step-by-step explanation:
Given
[tex]P = 80[/tex] ---- perimeter
Required
Write the area as a function of width
The perimeter of a rectangle is:
[tex]P =2(l + w)[/tex]
Where
[tex]l \to length\\ w \to width[/tex]
So, we have:
[tex]80 = 2*(l+w)[/tex]
Divide by 2
[tex]40 = l + w[/tex]
Make l the subject
[tex]l =40 - w[/tex]
The area of a rectangle is:
[tex]A = l * w[/tex]
Substitute: [tex]l =40 - w[/tex]
[tex]A = (40 - w) * w[/tex]
Hence, the function is:
[tex]A(w) = (40 - w) * w[/tex]
