I dont understand index form please help

When we multiply powers with the same base, we add the powers together. This will give us:
[tex]\frac{3^8*3^4}{3^2 * 3^8} \\\frac{3^{12} }{3^{10}}\\[/tex]
When we divide the fractions with the same base then we subtract the exponents:
3^12 / 3^10 = 3^12-10 = 3^2
I hope this helps! :)