Simple.....
you have [tex] \frac{18}{a} =7
[/tex]
to find what a is....simplify/multiply both sides....
[tex]a* \frac{18}{a} =7*a[/tex]
simplifying it too....
18=7a
[tex] \frac{18}{7} = \frac{7a}{7} [/tex]
[tex] \frac{18}{7} =a[/tex]
Thus, your answer, C.
