Question

models the cost, in dollars, of a rug with width x feet. What is the cost of a rug that is 9 feet wide?

Answer 1

we are given

cost function as

$f(x)=2.15(2x^2-4x-6)$

we can plug x=9

and we get

$f(9)=2.15(2(9)^2-4*9-6)$

we can simplify it

and we get

$f(9)=258$...........Answer

Answer 2

Cost of Rug of width x = f(x) = 2.1 5 ( 2x^2 -4x -6 )

To find cost of Rug of width 9 feet , we can replace x with 9 .

This gives us f(9 ) = 2.15 ( 2 * 9^2 - 4*9 -6 )

First we work on exponent then we do multiplication inside parenthesis then we would simplify the stuff inside parenthesis

. f(9) = 2.15 ( 2* 81 - 36 - 6)

f(9) = 2.15 ( 162 - 36 -6)

f(9) = 2.15 ( 120)

= 258

Answer = $258