Step 1. Gather like terms
\(13*3 x^{2} xy^{3} y^{5}\)
Step 2. Use product rule: \(x^{a} x^{b} = x^{a+b}\)
\(13*3 x^{2+1} y^{3+5}\)
Step 3. Simplify \(2+1\) to \(3\)
\(13*3 x^{3} y^{3+5}\)
Step 4. Simplify \(3+5\) to \(8\)
\(13*3 x^{3} y^{8}\)
Step 5. Simplify
\(39 x^{3} y^{8}\)
Done!
