Simplify. Express your answer using positive exponents.9r8r79

The expression you provided is 9r^8 * r^79.

To simplify this, you need to use the rule of exponents which states that when you multiply two exponents with the same base, you add the powers.

Here, the base is 'r' and the powers are 8 and 79.

So, you add 8 and 79 to get 87.

The coefficient 9 remains the same.

Therefore, the simplified expression is 9r^87.