Respuesta :
to write them both with a common denominator, we simply multiply one by the other's denominator, so let's proceed,
[tex]\bf \cfrac{7}{9}\cdot \cfrac{3}{3}\implies \boxed{\cfrac{21}{27}}\qquad \qquad \qquad \cfrac{2}{3}\cdot \cfrac{9}{9}\implies \boxed{\cfrac{18}{27}}[/tex]