### Instruction: If $*$ represents an operation defined by $a*b=a^b+b$, find $(1*2)*3$.### Response: This problem involves a custom operation, so I need to follow the definition given in the problem.
First, I need to evaluate what is inside the parentheses, which is $1*2$.
By the definition of $*$, $1*2=1^2+2=3$.
Now I have $(1*2)*3=3*3$.
Again, by the definition of $*$, $3*3=3^3+3=27+3=30$.