To simplify the expression \( k^{120} \cdot k^{30} \), you can use the rule of exponents that states \( a^m \cdot a^n = a^{m+n} \).
So, in this case:
\[ k^{120} \cdot k^{30} = k^{120 + 30} = k^{150} \]
Therefore, the simplified expression is:
k150