Let,
[tex]\begin{gathered} (x_1,y_1)=(9,4) \\ (x_2,y_2)=(-8,4) \end{gathered}[/tex]The expression to calculate the distance between two points is,
[tex]d=\sqrt[]{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]Substitute values in the above expression.
[tex]\begin{gathered} d=\sqrt[]{(-8-9)^2+(4-4)^2} \\ d=\sqrt[]{(-17)^2+0^2} \\ d=\sqrt[]{289} \\ d=17 \end{gathered}[/tex]Thus, the points (9,4) & (-8,4) are 17 unit apart on the coordinate plane.
