###### Carl Horowitz

University of Michigan
Runs his own tutoring company

Carl taught upper-level math in several schools and currently runs his own tutoring company. He bets that no one can beat his love for intensive outdoor activities!

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# Common Algebra II Mistakes - Problem 3

Carl Horowitz
###### Carl Horowitz

University of Michigan
Runs his own tutoring company

Carl taught upper-level math in several schools and currently runs his own tutoring company. He bets that no one can beat his love for intensive outdoor activities!

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A common mistake in dealing with square roots is that when we’re dealing with square root of a sum to split this up as the square rots of each thing individually. To prove to you that this actually can’t be the case, we’re going to take an example that works out quite nicely.

The square root of 9 plus 16. We have to add inside so we end up with the square root of 2. Square root of 25 is simply 5. If we were to try to split this up, we would get the square root of 9 plus the square root of 16. Square rot of 9 is 3, square root of 16 is 4 and we end up getting 7.

What we show here is that we cannot spit up a sum if we’re dealing inside of a square root. Really the square root of x plus y is just the square root of x plus y. there’s nothing we can do with it so don’t try to split it up because you’re not going to get the right answer.