9.4.3 Curvilinear integrals

(a) Problem: Calculate the line integral from point \( A \) to point \( C \) along three different paths: \[ \begin{array}{l} A(0 ; 1), \quad B(3 ; 1), \quad C(3 ; 10) \\ I=\int_{\ell}(2 y+x) d x+(2 x-1) d y \end{array} \]