To find the missing exponent in the equation \( h^{450} \cdot h^{?} = h^{215} \), we can use the properties of exponents. Specifically, when multiplying terms with the same base, we add the exponents:
\[ h^{450 + ?} = h^{215} \]
From this, we can set up the equation:
\[ 450 + ? = 215 \]
Now, we can solve for the missing exponent \( ? \):
\[ ? = 215 - 450 \] \[ ? = -235 \]
Therefore, the missing exponent is \( -235 \).