Answer :
We are going to multiply [tex] \frac{21}{35}[/tex] by 2.
[tex] \\ \frac{21}{35}*2= \frac{42}{70} \\ [/tex]
Therefore, [tex] \frac{21}{35}[/tex] is equivalent to [tex] \boxed{ \frac{42}{70}}[/tex]. Hoped I helped. :)