Question

Given the function a(x)=4x−8 with range R: {0,4,8}, which of the following represents the domain, D of function a?

Select one:
A. D: {0, 1, 2}
B. D: {2, 2, 6}
C. D: {-2, -1, 0}
D. D: {2, 3, 4}

Answer 1

Option D.

Explanation:

The given function is

`a(x)=4x-8`

We need to find the domain of the function for range R:{0,4,8}.

Domain is the set of input values and range is the set of output values.

Substitute a(x)=0 in the given function.

`0=4x-8`

`-4x=-8`

`x=2`

Substitute a(x)=4 in the given function.

`4=4x-8`

`12=4x`

`3=x`

Substitute a(x)=8 in the given function.

`8=4x-8`

`16=4x`

`4=x`

The input values of function for outputs 0, 4 and 8 are 2, 3 and 4 respectively.

Domain = {2,3,4}

Therefore, the correct option is D.

Answer 2

the correct option is D

4(2)-8= 0

4(3)-8 = 4

4(4)-8 = 8