Simple...
you have: \(\frac{z}{12} =9\)
To solve this..you want to isolate the variable (z)...
1.) Cancel out the 12 by multiplying it out--->>>>
\(12* \frac{z}{12} =9*12\)
Leaving you with....
z=108
Then-->>>
5g=230
Again, isolate the variable....
1.) Do this by dividing both sides by 5.....
5g=230
\(\frac{5*g}{5} = \frac{230}{5}\)
g=46
Thus, your answer.