Răspuns :
[tex]AB= \sqrt{( x_{2}- x_{1})^2 +( y_{2}- y_{1})^2 }= \sqrt{(2-5)^2+(3+1)^2} = \sqrt{9+16}=5 [/tex]
[tex]AB= \sqrt{(xB-xA)^{2}+ (yB-yA)^{2}} [/tex]
[tex]AB= \sqrt{(2-5)^{2}+ (3+1)^{2}} =\sqrt{(-3)^{2}+ (4)^{2}}= \sqrt{25} =5 cm[/tex]
[tex]AB= \sqrt{(2-5)^{2}+ (3+1)^{2}} =\sqrt{(-3)^{2}+ (4)^{2}}= \sqrt{25} =5 cm[/tex]