The perimeter of a rectangular book is 48 inches. How do you express the length of the book as a function of the width?

1 Answer
May 28, 2016

f(w)=-w+24

Explanation:

Recall that the perimeter of a rectangle is given by,

color(blue)(|bar(ul(color(white)(a/a)P=2(l+w)color(white)(a/a)|)))

where:
P=perimeter
l=length
w=width

Hence, to create an expression for the length, substitute 48 for P and rearrange for l.

P=2(l+w)

48=2(l+w)

48/2=l+w

l=24-w

Replacing l with f(w),

color(green)(|bar(ul(color(white)(a/a)color(black)(f(w)=-w+24)color(white)(a/a)|)))