A common denominator is a common multiple of two or more denominators
equivalent fraction to 1/3
we can multiply the numerator and denominator of a fraction by the same number to obtaian an equivalent fraction
Then if we multiply 1/3 by 2
[tex]\frac{1\times2}{3\times2}=\frac{2}{6}[/tex]then option A is right
If we multiply 1/3 by 3
[tex]\frac{1\times3}{3\times3}=\frac{3}{9}[/tex]then option B is right too
equivalent fraction to 5/7
if we multiply 5/7 by 3
[tex]\frac{5\times3}{7\times3}=\frac{15}{21}[/tex]then option C is right
if we multiply 5/7 by 2
[tex]\frac{5\times2}{7\times2}=\frac{10}{14}[/tex]then A option is right too