Question

C la 58 ÷ C la 39 ÷ C la 9

Answer 1

    $c^{58}:c^{39}:c^9 = c^{(58-39-9)} = \boxed{c^{10}}$

Answer 2

$c^5^8:c^3^9:c^9=c^5^8^-^3^9:c^9=c^1^9:c^9=c^1^9^-^9=c^1^0$