To solve the problem given in the figure attached, you must apply the proccedure shown below:
1. You have the following expression given in the problem:
x^19 = y
2. By definition, you have:
logb(x)=y
b^y=x
3. Therefore, you have:
x^19 = y
logx(y)=19
4. Then, as you can see, the answer is: logx(y)=19