Answer:
The answer is the option A
[tex]x^{3}y^{4}[/tex]
Step-by-step explanation:
we know that
The lowest common denominator it is the smallest positive integer that is a multiple of each denominator in the set
In this problem we have
[tex]\frac{3}{x^{3}y}[/tex] and [tex]\frac{7}{xy^{4}}[/tex]
so
between
[tex]x^{3}y[/tex] and [tex]xy^{4}[/tex]
the lowest common denominator is equal to
[tex]x^{3}y^{4}[/tex]
