Question

What is the range if f(x) = 3x - 9 and domain: -4,-3,0,1,8?

Answer 1

`y in{-21,-18,-9,-6,15}`

Explanation:

`"to obtain the range substitute the given values in the "`
`"domain into "f(x)`

`f(-4)=-12-9=-21`

`f(-3)=-9-9=-18`

`f(0)=-9`

`f(1)=3-9=-6`

`f(8)=24-9=15`

`"range is "y in{-21,-18,-9,-6,15}`

Answer 2

Range = `{-21, -18, -9, -6, +15}`

Explanation:

Here we have a lineal function `f(x) = 3x-9` defined for `x={-4,-3,0,1,8}`

The slope of `f(x)=3 -> f(x)` is linear increasing.

Since `f(x)` is linear increasing, its minimum and maximum values will be at the minimum and maximum values in its domain.

`:. f_min = f(-4) = -21`

and `f_max = f(8) = 15`

The other values of `f(x)` are:

`f(-3) = -18`
`f(0) = -9`
`f(1) = -6`

Hence the range of `f(x)` is `{-21, -18, -9, -6, +15}`