The area of a rectangle is given by the function Ax x2 6x

The area of a rectangle is given by the function A(x) = -x^2 + 6x + 20. Find the maximum value of its area. a. 47 square units b. 29 square units c. 7 square units d. 90 square units e. 15 square units

Solution

A(x)=-x²+ 6x+20

Maximum area is maximum value of x and x is maximum at the vertex

x=-/2a= -6/-2=3

A(3)= -3²+6(3) + 20 = 29 square units

Correct option is b.