Question

Which of the following functions has the largest value when x = 3? (1 point)

c(x) = 3x2 + 5x + 22
j(x) = 12x
a(x) = 9x


All the functions are equal at x = 3.
c(x)
j(x)
a(x)

Answer 1

Answer: a(x) =
`9^(x)`

An easy way to find this is by going on a graphing website like desmos. You simply put all of the equations into desmos and it will automatically recognize them as exponential functions, quadratic functions, etc. Once you do this you can write out x = 3 to create a line to compare them all.

If you can't use a graphing site, then simply insert 3 for x in each equation.

c(x) = 3
`(3)^(2)` + 5(3) + 22

27 + 15 + 22 = 64

j(x) = 12(3)

12 * 3 = 36

a(x) =
`9^((3))`

9 * 9 * 9 or 9^3 = 729

c(x) = 64

j(x) = 36

a(x) = 729

Answer 2

x = 3

c(x) = 3x² + 5x + 22
⇒ c(3) = 3(3²) + 5(3) + 22
⇒ c(3) = 3(9) + 15 + 22
⇒ c(3) = 27 + 15 + 22
⇒ c(3) = 64

j(x) = 12x
⇒ j(3) = 12(3)
⇒ j(3) = 36

a(x) = 9x
⇒ a(3) = 9(3)
⇒ a(3) = 27

c(x) = 3x² + 5x + 22 is the function that has the largest value when x = 3.

False. Not all functions are equal at x = 3.