Question

\sqrt{20 + x} is continuous on the interval:
[-20, infinity), is this correct?

Answer 1

yes

Answer 2

What is the domain of the square root? >= 0
So if you put -20 inside the square root what do you get? 0
Which is a valid point of the domain, so the function will be continuous in this interval.

Answer 3

\[20+x \ge 0\rightarrow x \ge -20\]in interval notation\[[-20,\infty)\]

Answer 4

yup