Question

A rectangle has a length of 11 inches and a width of 7 inches. If the length is increased by xx inches and the width increased by three times that amount, express the area of the rectangle as a function of x.

A(x)=??

Answer 1

A(x) = (11+x)(7+3x)
A(x) = 77 + 33x + 7x + 3x^2
A(x) = x^2 + 40x + 77