<PRE><B>Question 66032</B>
simplify

5 times the square root of 7/20 - 2 times the square root of 20/7 - 3 times the square root of 560

5sqrt(7/20)-2sqrt(20/7)-3sqrt560=
5sqrt(7/20)-2sqrt(20/7)-3sqrt((20)(4)(7))  which equals:
5sqrt(7/20)-2sqrt(20/7)-6sqrt((20)(7)) 

We need a common denominator.  We can get this by multiplying the numerator and denominator of each term by sqrt((20)(7)) --- the LCM.  This gives us:

5(sqrt7)(sqrt7)-2(sqrt20)(sqrt20)-6(sqrt((20)(7))(sqrt((20)(7))) which equals:

[5(7)-2(20)-6(20)(7)]/sqrt((20)(7) simplifying we get:
(35-40-840)/sqrt(140)=-845/sqrt(140)

Multiply numerator and denominator by sqrt(140) to get rid of the radical in the denominator and we get:

-845sqrt(140)/140  =
-845sqrt((4)(35))/140= 
-1690sqrt(35)/140= divide both numerator and denominator by 10

-169sqrt(35)/14

That should be it unless I made a mistake.

CK by using a calculator

Hope this helps---ptaylor








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