The given expression is,
[tex]r^{13}\times r^{11}\times r^7[/tex]Exponents are used to express large numbers in shorter form to
make them easy to read, understand, compare and operate upon. If we write,
[tex]a^m[/tex]a is the base and m is the power. So for an expression where, a constant base with different powers are being multiplied, we have, from the property of exponents,
[tex]a^m\times a^n=a^{m+n}[/tex]Using the same property of exponnets, we can write the given expression as,
[tex]r^{13}\times r^{11}\times r^7=r^{13+11+7}=r^{31}[/tex]Thus the answer is r^31.
