Question 124280
Domain is all x such that f(x) makes sense. Values inside a square root sign must be greater than or equal to 0.
{{{x^2-49>=0}}}
{{{x^2>=49}}}
{{{x>=7}}}
{{{x<=-7}}}
The domain is therefore all x except the range (-7,7) or the domain is 
({{{-infinity}}},{{{7}}}] U [{{{7}}},{{{-infinity}}})
The brackets indicate that -7 and 7 belong in the domain.
The range is from [{{{0}}},{{{infinity}}}).