I have a few math questions involving dividing radicals with extra variables... Help please?!?!?!
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\[3+2\sqrt{5}\div2\sqrt{5}-3\] This is one example, could anyone help explain how to work this?
Oh That is a fraction btw...
i am going to make a guess that this is really \[\frac{3+2\sqrt5}{2\sqrt5-3}\]
multiply top and bottom by 2*sqrt(5) +3
and simplify
remember sqrt(x)*sqrt(X) = x
You'll need to use the difference of two squares here: \[(a+b)(a-b)=a^2+b^2\]So we multiply the top and bottom by 2sqrt{5}+3: \[\frac{3+2\sqrt{5}}{2\sqrt{5}-3}* \frac{2\sqrt{5}+3}{2\sqrt{5}+3} = \frac{(3+2\sqrt{5})(2\sqrt{5}+3)}{(2\sqrt{5})^2-3^2} \] Simplify for your answer :)
2*sqrt(5) *2*sqrt(5) = 4*5 = 20
Okay, so my next question, how would I simplify?
3*2*sqrt(5) + 3*3 + 2sqrt(5)*2sqrt(5) + 2sqrt(5)*3 That is the top .... remember the FOIL thing
(x+y)(a+b) = x*a + x*b + y*a + y*b
I think it stood for Firsts, Outers, Inners, Lasts
OH, Okay.
6*sqrt(5) + 9 + 4*5 + 6sqrt(5)
12 sqrt(5) + 29 that is the numerator
\[(2\sqrt{5}-3)(2\sqrt{5}+3) = \]
4*5 +6sqrt(5) - 6 sqrt(5) - 9
= 20 - 9 =11 for the Denominator
so \[\frac{ 12\sqrt{5}+29 }{ 11 }\]
If you ever see a quantity like \[(\sqrt{x}+a)\] in the denominator, then multiply both numerator and denominator by \[(\sqrt{x}-a)\]
It will get rid of the radical in the denominator, which is not simplified
OKay, thank you, would you be willing to help with a few more?
sure
can you open a new thread and tag me
Alright, let me close this question and open a new one.
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