Answer:
[tex]f(15)=525\ ft^{2}[/tex]
f(15) is the area of the rectangular garden for a width of 15 ft
Step-by-step explanation:
we know that
[tex]f(x)=x(2x+5)[/tex]
where
x----> is the width of the rectangular garden
(2x+5) ----> is the length of the rectangular garden
so
f(15) -----> is the value of f(x) for x=15 ft
That means
f(15) is the area of the rectangular garden for a width of 15 ft
substitute the value of x and solve
[tex]f(15)=15(2(15)+5)[/tex]
[tex]f(15)=525\ ft^{2}[/tex]
