[tex] \frac{ {12}^{6} }{ {12}^{2} } [/tex]
Here you subtract the exponent from the other
[tex] \frac{ {12}^{6} }{ {12}^{2} } = {12}^{4} [/tex]
For the second one you multiply the exponents as so
[tex]3 \times 5 = 15[/tex]
[tex] { ({10}^{3} )}^{5} = {10}^{15} [/tex]
