Question

How do I write a function rule for the area of a rectangle whose length is 4in. more than its width. What is the area of the rectangle when its width is 8in.?

Answer 1

Let the width be w, then length = w + 4
Area = length x width = w(w + 4) = w^2 + 4w
f(w) = w^2 + 4w

for w = 8 in
Area = (8)^2 + 4(8) = 64 + 32 = 96 in^2