Question

Rationalise 120(13-✓7)/13+✓7

Answer 1

multiple (root 13 - 7 ) by numerator and denominator
and use formula:-
a sq - b sq. = (a+b)(a-b)
(a-b) whole sq. = a sq. + be sq. - 2ab
hope it helped...
Rahul

Answer 2

solution:

given: 120(13-$\sqrt{7}$)/(13+$\sqrt{7}$)
to rationalize:

       =120(13-$\sqrt{7}$)/(13+$\sqrt{7}$) x 13-$\sqrt{7}$)/13-$\sqrt{7}$)
       $=120(13- (\sqrt{7}))^2/(13^2- (\sqrt{7})^2)$
   [tex]=120(169-26 \sqrt{7}+7)/(169-7) [/tex]
     $=120(176+26 \sqrt{7})/162$