Question

Растояние между точками A(-1;7); B(1;3);

Answer 1

А(-1;7)
В(1;3)

$|AB|= \\ = \sqrt{(x_B - x _A )^{2} + (y_B - y _A )^{2}} = \\ = \sqrt{(1 - ( - 1)) ^{2} + (3 - 7)^{2} } = \\ = \sqrt{ {2}^{2} + {4}^{2} } = \sqrt{20} = 2 \sqrt{5}$