como resolver as abcissas

a)

\(\Longrightarrow M={A+B \over 2}\)

\(\Longrightarrow M={(3,-2)+(-1,-6) \over 2}\)

\(\Longrightarrow M={(3-1,-2-6) \over 2}\)

\(\Longrightarrow M={(2,-8) \over 2}\)

\(\Longrightarrow \fbox {$ M=(1,-4) $}\)

b)

\(\Longrightarrow M={A+B \over 2}\)

\(\Longrightarrow M={1\over 2} \Big [({1 \over 2},{1 \over 3})+(-1,{2 \over 3}) \Big ]\)

\(\Longrightarrow M={1\over 2} ({1 \over 2}-1,{1 \over 3}+{2 \over 3}) \)

\(\Longrightarrow M={1\over 2} (-{1 \over 2},1) \)

\(\Longrightarrow \fbox {$ M= (-{1 \over 4},{1 \over 2}) $}\)

A) Xm= (Xa+Xb)/2;

     Xm= (3-1)/2= 1:

    Ym= (ya+yb)/2;

    Ym= [-2 + (-6)]/2= -4;     Logo, M (1;-4)

B) Xm=[1/2+ (-1)]/2= -0.5/2= -0.25 ou 1/4

   Ym= (1/3+2/3)/2=

   [(1+2)/3]/2= 1/2= 0.5 ou 1/2;  Logo, M (0.25;0.5) ou M(1/4;1/2)