Find an expression for the perimeter of a rectangle with the given area.

Question

A= x² + 24x -81

Answer 1

Assuming that one factor of A is the length L and the other is the width W,

 

A(x) = x² + 24x - 81 = (x - 3)(x + 27) = LW or WL

 

P(x) = 2(L + W) = 2[(x - 3) + (x + 27)] = 2[(x + 27) + (x - 3)]

 

You can simplify and finish from here.