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Mathematics 8 Online
OpenStudy (anonymous):

sqrt 3 * sqrt 21

OpenStudy (anonymous):

jhonyy9 (jhonyy9):

sqrt3 *sqrt(7*3) = 3sqrt7

OpenStudy (anonymous):

thank you :)

OpenStudy (diyadiya):

\[\sqrt{21}=\sqrt{3}\times \sqrt{7}\]\[\sqrt{3} \times \sqrt{21}=\sqrt{3}\times \sqrt{3} \times \sqrt{7}\]\[\sqrt{3} \times \sqrt{3} =3 \]Therefore\[3\sqrt{7}\]

OpenStudy (anonymous):

thanks guys, and thank you @Diyadiya for the explanation in detail! :)

OpenStudy (diyadiya):

Glad to help :)

OpenStudy (anonymous):

can i ask one more question?

OpenStudy (diyadiya):

Sure Post it

OpenStudy (anonymous):

OpenStudy (diyadiya):

\[\frac{5}{\sqrt{3}} = \frac{5 \times \sqrt{3}}{\sqrt{3} \times \sqrt{3}}\]

OpenStudy (diyadiya):

Rationalise the denominator means to remove the radical from the denominator so we multily the numerator and denominator with the same radical ok ? what will be the answer ? what is sqrt 3 x sqrt 3 ?

OpenStudy (anonymous):

3

OpenStudy (diyadiya):

Yes so answer is ?

OpenStudy (anonymous):

i think the first one

OpenStudy (diyadiya):

Yes ,Do you understand why ?

OpenStudy (anonymous):

i do now! :) thanks for all your help

OpenStudy (diyadiya):

No problem :)

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