A(2,6) B(2,1) C(8,-1) Aria poti sa o determini cu determinantul format de cele 3 puncte: [latex] left[egin{array}{ccc} x_{1} & y_{1} &1\ x_{2} & y_{2} &1\ x_{3} & y_{3} &1end{array} ight] [/latex] [latex] left[egin{array}{ccc}2&6&1\2&1&1\8&-1&1end{array} ight] [/latex] Calculam determinantul:  =2-2+48-8+2-12=20 Aria=20