Answer: \(y^9\)
Step-by-step explanation:
The product law of exponent says that for any arbitrary number a, we have:
\(a^m\times a^n=a^{m+n}\), where powers m and n are any number.
The given expression: \(y^4\cdot y^5\)
Using product law of exponents , we get
\(y^4\cdot y^5\\\\=y^{4+5}\\\\=y^9\)
Hence, the simplified expression of the given expression is \(y^9\).
