Question
Find distance between point $A(-1,1)$ and point $B(5,-7)$ :
Solution: Suppose $A\left(x_1, y_1\right)$ and $B\left(x_2, y_2\right)$
$x_1=-1, y_1=1 \text { and } x_2=5, y_2=-7$
Using distance formula,
$ d(A, B)=\sqrt{\left(x_2-x_1\right)^2+\left(y_2-y_1\right)^2}$
$\therefore d(A, B)=\sqrt{\square+[(-7)+\square]^2}$
$\therefore d(A, B)=\sqrt{\square}$
$\therefore d(A, B)=\square $
Solution: Suppose $A\left(x_1, y_1\right)$ and $B\left(x_2, y_2\right)$
$x_1=-1, y_1=1 \text { and } x_2=5, y_2=-7$
Using distance formula,
$ d(A, B)=\sqrt{\left(x_2-x_1\right)^2+\left(y_2-y_1\right)^2}$
$\therefore d(A, B)=\sqrt{\square+[(-7)+\square]^2}$
$\therefore d(A, B)=\sqrt{\square}$
$\therefore d(A, B)=\square $
