1.
[tex]A. \ x \geq 3,2[/tex]
2.
[tex]A = (1,5), \ \ \ \ \ \ B = (2,3)\\A = (x_{A}, y_{A}), \ \ \ B = (x_{B}, y_{B})\\\\|AB| = \sqrt{(x_{B}-x_{A})^{2} + (y_{B}-y_{A})^{2}}\\\\|AB| = \sqrt{(2-1)^{2}+(3-5)^{2}} = \sqrt{1^{2}+(-2)^{2}} = \sqrt{1+4} = \sqrt{5}\\\\Odp. \ C.[/tex]
3.
[tex]P = (4,2), \ \ \ \ Q = (0,8)\\P = (x_1,y_1), \ \ Q = (x_2,y_2)\\\\S = (\frac{x_1+x_2}{2}; \ \frac{y_1+y_2}{2})\\\\S = (\frac{4+0}{2}; \ \frac{2+8}{2})\\\\S = (2,5)\\\\Odp. \ A.[/tex]
3.
[tex]S = (-1,1), \ \ A = (3,5)\\\\S_{x} = \frac{3+x}{2}\\\\-1=\frac{3+x}{2} \ \ /\cdot2\\\\3+x = -2\\\\x = -5\\\\\\S_{y} = \frac{5+y}{2}\\\\1 = \frac{5+y}{2} \ \ /\cdot2\\\\5+y = 2\\\\y = -3\\\\S = (-5; -3)\\\\Odp. \ B.[/tex]
