ajutati maaaa ex 2...

[tex]d(A,B)=\sqrt{(x_B-x_A)^2+(y_B-y_A)^2} =13\ \ \ \ |^2\\\\\\169=(3-a)^2+25\\(3-a)^2=144\\3-a=12\ sau \ 3-a=-12\\\\a=-9\ sau\ a=15[/tex]
[tex]M(\frac{x_B+x_A}{2},\frac{y_B+y_A}{2} )\\\\\\M(-2,4)[/tex]