## Introductory Algebra for College Students (7th Edition)

$y^{12}$
Using $x^a \cdot x^b=x^{a+b}$ or the product rule, the given expression, $y\cdot y^{11} ,$ simplifies to \begin{array}{l}\require{cancel} y^{1+11} \\\\= y^{12} .\end{array}