# How do you simplify  y^4*y^5?

${x}^{\textcolor{red}{a}} \times {x}^{\textcolor{b l u e}{b}} = {x}^{\textcolor{red}{a} + \textcolor{b l u e}{b}}$
${y}^{\textcolor{red}{4}} \times {y}^{\textcolor{b l u e}{5}} \implies {y}^{\textcolor{red}{4} + \textcolor{b l u e}{5}} \implies {y}^{9}$