SOLUTION: explain why x=4 is not in the domain of the function f(x)= square root x-5?

Question 1034868: explain why x=4 is not in the domain of the function f(x)= square root x-5?
Answer by harpazo(655) (Show Source): You can put this solution on YOUR website!
If you replace x with 4 in the given function the answer becomes root(-1).
The root of negative numbers does not exist in the real number system.
This is why x cannot be 4. The value of x = 4 stands outside the domain of the
function.
Prove:
f(x) = root(x - 5)
f(4) = root(4 - 5)
f(4) = root(-1)
So, x = 4 is undefined for this function.
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