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41 votes
41 votes
So I was wondering how to do this, 15-
√(x+2) what value of x does the expression make sense

User Andersson Melo
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2.7k points

2 Answers

10 votes
10 votes

Answer:

x >= -2

Explanation:

For real numbers (like, for graphing or applications) the number inside the square root symbol must be a positive number. So, if x is -3, -4, -5 you will get a negative number inside the square root. If x is -2, you get a zero, which is fine(allowed, no problem) If x is -1, you get a 1 inside there, which is no problem. Any positive number for x yields a positive number inside the square root.

So x must be greater than -2.

Saying what x is or can be is what is "the domain"

Domain: x >= -2

This is set notation.

Interval notation looks like this:

[-2, infinitysymbol)

Simply, x >= -2

User Sbooth
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2.8k points
11 votes
11 votes

Answer:

Explanation:

The question makes sense for all values of x, but I imagine that is not exactly what you mean.

I think you mean for what values of x does the question produce a real square root?

The answer is as long as x + 2 does not drop below 0, the results will be real.

Put mathematically x ≥ -2 gives a real result. For now just don't try and take the square root of a minus number.

User Simbi
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2.6k points