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# Radicals and rational exponents — Basic example

Watch Sal work through a basic Radicals and rational exponents problem.

## Want to join the conversation?

• Is there any way to practice this on here because that is what I really need to do.
• If you multiply the same square root with itself does it always just give you the number? For eg. (sqroot 2) * (sqroot 2) = 2.
• Yes. When you take the square root of something, you ask "What number multiplied by itself gives me my input?". When you take this number and multiply it by itself, like in the equation you so kindly provided, by definition you should get the input.
• if sqroot times sqroot is a whole number then how come when he multiplied the decimals in the sqroots it didn't come out as 0.5 but as a root 0.5
• You don't quite have it down.

Like Sal shows sqrt(a) * sqrt(b) = sqrt(a * b).

If both radicals are the same (a = b), then your case will be true. e.g.:
`sqrt(4) * sqrt(4) = sqrt(4 * 4) = 4`

I believe you were thinking of perfect squares, such as the example I just gave.

Hope this helps!
- Convenient Colleague
• Does the SAT consider plus or minus of an answer for a square root of a number or is it always positive? Ex: (square root of 4) = -2, so +/-2=-2, or does the SAT accept the answer +2 does not equal to -2.
• How often will I need to rationalize the denominator?
• But dont you also have to multiply the 3s?
(1 vote)
• nun of this is making any sense and i have to take a test tommorrow and i think imma fail like its an important test im talking bout algebra 1 eoc test can any one help me?
(1 vote)
• The only thing I can think of is to look up a bunch of YouTube videos on fractional exponents. There's a lot of great material out there if you look for it. 😉
(1 vote)
• Orrrr you can see the gcf is square root, square it, then have 0.4 x 1.25 which come to 0.5...... which is 1/2