The midpoint of a segment \(A(x_A;\ y_A);\ B(x_B;\ y_B)\\\\M_{AB}\left(\dfrac{x_A+x_B}{2};\ \dfrac{y_A+y_B}{2}\right)\)
A(-12;-3); B(3;-8)
\(M_{AB}\left(\dfrac{-12+3}{2};\ \dfrac{-3+(-8)}{2}\right)\to M_{AB}\left(\dfrac{-9}{2};\ \dfrac{-11}{2}\right)\to M_{AB}(-4.5;-5.5)\)
