Question 992342
Determine the values of the variable for which the expression is defined as a real number. (Enter your answer using interval notation.) 
square root of x^2 − 16 
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sqrt(x^2-16)
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For the value to be a Real Number, x^2-16 must be >= 0
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Solve:
x^2-16 >= 0
(x-4)(x+4) >= 0
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Ans: x >= 4 or x <= -4
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Cheers,
Stan H.
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