Question

How do you find the intervals on which the function is continuous given `y = sqrt(5x + 9)`?

Answer 1

`x in (-1.8, infty)`

Explanation:

The square root function cannot work with negative inputs. Therefore, we need to think about when the argument becomes negative. This is simple algebra:

`5x+9 < 0`
`5x < -9`
`x < -1.8`

So for any input `x < -1.8`, this function is undefined. However, for any input greater than that the function is well defined, so it's continuous on that interval.