\frac{2^{19}*27^3+15*4^9*9^4}{6^9*2^{10}+12^{10}}=
=\frac{(2^2)^9*2^1*(3^3)^3+3*5*4^9*(3^2)^4}{6^9*2^9*2+12^{10}}=
=\frac{4^9*2*3^9+3^1*3^8*4^9*5}{12^9*2+12^{10}}=
=\frac{3^9*4^9*2+3^9*4^9*5}{12^9*2+12*9*12}=
=\frac{12^9*2+12^9*5}{12^9(2+12)}=
= \frac{\not12^9(2+5)}{\not12^9*14}=\frac{7}{14}=\frac{1}{2}