Question

What is the domain of this function? {x| x > }

Answer 1

Notice that it starts at x = 0 with closed dot then it goes to the right.

So the domain would be {x | x ≥ 0}

Hope this helps.

Answer 2

The graph defines the function for all values of x greater than or equal to zero.
  {x | x ≥ 0}

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The solid dot at (0, 9) indicates x=0 is part of the domain. The arrow at the right end of the line indicates the domain extends to +∞.