Question 58689
Simplify (sqrt7)(sqrt14)
=sqrt(7^2*2)
=7sqrt2
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Simpilfy 5(sqrt5)-(sqrt20)
=5sqrt5-sqrt(4*5)
=5sqrt5-2sqrt5
=3sqrt5
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Simplify (sqrt5)(sqrt3) 
=sqrt15
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Determine whether (121)^1/3 is rational or irrational. This is the 3rd root of 121.
It is irrational because 121 is not a perfect cube.
Cheers,
Stan H.