Write $1296$ in exponential form using prime factorization.

If $7\times 7\times 7\times 7\times 7=7^k$, then the value of $k$ is

Write the exponential form of the given expression.

$3\times 3\times 3\times 5\times 5\times 5\times 5$

Write the exponential form of the given expression.

$2\times 2\times 2\times 3\times 3\times 3\times 3\times 5\times 5\times 5$