SOLUTION: Is 2-square root 5 rational or irrational number?

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Question 739933: Is 2-square root 5 rational or irrational number?
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
2-sqrt%285%29 is irrational because sqrt%285%29 is irrational.
You know that the result from adding, or subtracting, or multiplying rational numbers is always rational.
If a is rational, 2-a must be rational.
If 2-sqrt%285%29 was rational,
2-%282-sqrt%285%29%29=2-2%2Bsqrt%285%29=sqrt%285%29 would be rational,
but it is not.

NOTE:
Watch out for trick questions.
Sometimes rational numbers are written in an unusual way to make them look irrational, just to trick you.
sqrt%284%29=2 is a rational number, even when it is written as sqrt%284%29
Similarly, sqrt%289%2F4%29=3%2F2 is rational, and so is