1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 - 12

= ( 1 + 9 ) + ( 2 + 8 )  + ( 3 + 7 ) + ( 4 + 6 ) + 5 - 12

= 10 + 10 + 10 + 10 + 5 - 12

= 10 x 4 + 5 - 12

= 40 + 5 - 12

= 45 - 12

= 33

\(x^{50}=x\)

\(\Rightarrow x^{50}-x=0\)

\(\Rightarrow x\left(x^{49}-1\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x^{49}-1=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x^{49}=1\end{cases}\Rightarrow\orbr{\begin{cases}x=0\\x=1\end{cases}}}\)

11 + 8 = 19