The distance between two points A(x1,y1) and B(x2,y2) is given by:
[tex]d(A,B)=\sqrt[]{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
In this case we have the poitns Q(1,-1) and N(9,-8), then:
[tex]\begin{gathered} d(Q,N)=\sqrt[]{(9-1)^2+(-8-(-1))^2} \\ =\sqrt[]{(8)^2+(-7)^2} \\ =\sqrt[]{64+49} \\ =\sqrt[]{113} \end{gathered}[/tex]
Therefore, the distance between Q and N is:
[tex]d(Q,N)=\sqrt[]{113}[/tex]
