\[\boxed{\mathbf{940.ОК\ ГДЗ - домашка\ на}\ 5}\]
\[\mathbf{а)\ }\text{A\ }(2;7)\ и\ \text{B\ }( - 2;7):\]
\[AB = \sqrt{( - 2 - 2)^{2} + (7 - 7)^{2}} =\]
\[= \sqrt{16} = 4.\]
\[\mathbf{б}\mathbf{)\ }\text{A\ }( - 5;1)\ и\ \text{B\ }( - 5; - 7):\ \ \ \]
\[AB = \sqrt{( - 5 + 5)^{2} + ( - 7 - 1)^{2}} =\]
\[= \sqrt{64} = 8.\]
\[\mathbf{в)\ }\text{A\ }( - 3;0)\ и\ \text{B\ }(0;4):\ \ \ \]
\[AB = \sqrt{(0 + 3)^{2} + (4 - 0)^{2}} =\]
\[= \sqrt{25} = 5.\]
\[\mathbf{г)\ }\text{A\ }(0;3)\ и\ \text{B\ }( - 4;0):\ \ \ \]
\[AB = \sqrt{( - 4 - 0)^{2} + (0 - 3)^{2}} =\]
\[= \sqrt{25} = 5.\]