Question

The range of the function f(x) = x+5 is {7,9}. what is the function's domain?

A. {2,4}
B.{-2,-4}
C.{12,14}
D.{-12,-14}
E.{0,5}

Answer 1

A{2,4}.
f(x)= x+5
y=x+5
7=x+5
x=2
---------
y=x+5
9=x+5
x=4

Answer 2

Option A is correct

{2, 4} is, the function's domain.

Explanation:

Domain is the set of all values of x for which function f(x) is defined.

Range is the set of all complete value of f.

Given the function:

`f(x) = x+5`

The range of the function is {7, 9}

When f(x) = 7

then;

`x+5 = 7`

Subtract 5 from both sides we have;

x = 2

When f(x) = 9

then;

`x+5 =9`

Subtract 5 from both sides we have;

x = 4

⇒Domain = {2, 4}

Therefore, the function's domain is, {2, 4}