Question

calcule a distancia entre os pontos A(4,-1) e B(0,2)

Answer 1

$d_{AB}=\sqrt{(x_B-x_A)^2+(y_B-y_A)^2}\\ \\ d_{AB}=\sqrt{(0-4)^2+(2+1)^2}=\sqrt{(-4)^2+3^2}=\sqrt{16+9}=\sqrt{25}=5$