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anonymous
 5 years ago
If I have a "Dividing Radical Expressions" question and the denominator has something like 4+4 square roots of 5, would I need to times both of those numbers by the square root of 5?
anonymous
 5 years ago
If I have a "Dividing Radical Expressions" question and the denominator has something like 4+4 square roots of 5, would I need to times both of those numbers by the square root of 5?

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Owlfred
 5 years ago
Best ResponseYou've already chosen the best response.0Hoot! You just asked your first question! Hang tight while I find people to answer it for you. You can thank people who give you good answers by clicking the 'Good Answer' button on the right!

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Can you be more specific about what you're looking at? I can't quite understand your description.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0multiply top and bottom by\[4\sqrt{5}\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0\[(4+\sqrt{5})(4\sqrt{5})=165=11\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0so my equation is 3/ 4+4 square roots of 5. In order to solve the problem, there can be no radicals on the bottom half. Would I need to times both the 4 and the 4 square roots of 5 by the square root of 5?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Oh, as Satellite said. Multiply by the conjugate. \[(a + \sqrt{b})(a  \sqrt{b}) = a^2 b\] So if you have \(a + \sqrt{b}\) you would multiply by \(a  \sqrt{b}\) and vice versa.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0If you did that, you would get: \[3/(4+4\sqrt{5})=3 \sqrt{5}/(20+4\sqrt{5})\] This does not cancel the square roots in the denominator so, instead, multiply the top and bottom by the conjugate of the denominator: \[44\sqrt{5}\] This gives: \[3/(4+4\sqrt{5})=3(44\sqrt{5})/(4+4\sqrt{5})(44\sqrt{5})=(1212\sqrt{5})/(64)\] There are no square roots in the denominator of this expression so your problem is solved.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0So what if the equation was that the alone 4 was negative

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0The part you change the sign on is the part with the radical.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0sorry i did not read carefully. if it was \[4+4\sqrt{5}\] you multiply by \[44\sqrt{5}\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0When I use the conjugated form, do I need to change the negative 3 to a positive 3?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0multiply by the 'conjugate'

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0conjugate of \[a+b\] is \[ab\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0what if it was negitive a + b? then what would it be?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0With square roots, the conjugate of \[a +\sqrt{b}\] is \[a\sqrt{b}\]Basically, change the sign on the square root to find the conjugate.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0the point being that \[(a+b)(ab)=a^2b^2\] so for example \[(3+\sqrt{2})(3\sqrt{2})=3^2)(\sqrt{2})^2=92=7\]

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0or \[(\sqrt{5}3)(\sqrt{5}+3)=(\sqrt{5})^23^2=59=4\] etc

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Yes, multiplying by a conjugate always cancels the square roots.
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