Question 339095
(1) sqrt of 7 divided by the sqrt of 18
= {{{sqrt(7/18)}}}
= {{{sqrt(14/36)}}}
= {{{sqrt(14)/6}}}
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(2) sqrt of 27 divided by sqrt of 16
Hint:  27 = 3*9 and 16 = 4*4
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(3) 6 divided by 3-sqrt of 18
{{{6/(3-sqrt(18))}}}
Multiply NUM and DEN by the conjugate of the DEN
= {{{6(3+sqrt(18))/((3+sqrt(18))*(3-sqrt(18)))}}}
= {{{(18 + 6sqrt(18))/(9 - 18)}}}
= {{{(18 + 18sqrt(2))/(-9)}}}
= {{{-2 - 2sqrt(2)}}}