Question

If f(x)=x-3, which inequality can be used to find the domain of f(x)?

Answer 1

Given that,

$f(x) = \sqrt{x-3}$

To find,

The domain of f(x).

Solution,

We have, $f(x) = \sqrt{x-3}$

To find domain,

The term under the square root must be positive or null as follows :

$x-3\ge 0$

Adding 3 both sides

$x-3+3\ge 0+3\\\\x\ge 3$

So, the domain is x-3>0 .