Question 193941
5-sqrt2,  conjugate  is  "5 + sqrt2"
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if  the  original  was  " + ",  the  conjugate  would  be  " - "
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These  are  important  to  radicals,  because  we  must  clear  the  denominators  of  radicals
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for  example,
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1 / (5-sqrt2),  multiply  num  and  den  by  conjugate, ( 5+ sqrt2)
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1*(5+sqrt2) / (  (5-sqrt2) (5+sqrt2) )
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(5 +sqrt2) / ( 25 +5sqrt2  -5sqrt2 -(sqrt2)^2  )
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(5 +sqrt2) / (25-2)
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(5+sqrt2 / 23