[tex] \large \sf \pink{Answer: }[/tex]
[tex] \large \purple{ \boxed{ \frac{16}{21}}}[/tex]
[tex] \large \sf \pink{Explanation:}[/tex]
[tex] \sf \large{ \frac{3}{7} + \frac{3}{9}}[/tex]
[tex] \sf \large{ \frac{3}{7} + \frac{1 \times 3}{3 \times 3}}[/tex]
[tex] \sf \large{ \frac{3}{7} + \frac{1}{3}} [/tex]
[tex] \sf \large\frac{3 \times 3}{21} + \frac{1 \times 7}{21}[/tex]
[tex] \sf \large{ \frac{9}{21} + \frac{7}{21}}[/tex]
[tex] \sf \large{ \frac{(9 + 7)}{21}}[/tex]
[tex] \sf \large \purple{ = \frac{16}{21}}[/tex]
