[tex]\displaystyle\bf\\\text{Daca avem: }\\\\A(x_1,~y_1)~si~B(x_2,~y_2)\\\\\text{atunci: }\\\\AB=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\\\\Rezolvare:\\\\Avem:~~A(0,3)~si~B(1,-1)\\\\Lungimea~segmentului~AB~este:\\\\AB=\sqrt{(1-0)^2+(-1-3)^2}=\sqrt{(1)^2+(-4)^2}=\sqrt{1+16}=\boxed{\bf\sqrt{17}}[/tex]
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