Ta có : $$\begin{cases} u_1+2u_2=19\\u_5-u_3=10 \end{cases}$$
<=>$$\begin{cases} u_1+2(u_1+d)=19\\u_1+4d-u_1-2d=10 \end{cases}$$
<=>$$\begin{cases} 3u_1+2d=19\\2d=10 \end{cases}$$
<=>$$\begin{cases} u_1=3\\d=5 \end{cases}$$
Suy ra : S=u_1+u_2+...+u_{2024}={2024[2.3+(2024-1).5]}/{2}=10242452