Help me with math and explain it in a short way

The points X and Y on the graph have the coordinates:
X : (-5, -3)
Y: (4, -3)
Solution
To find the distance (d) between the points X and Y on the coordinate plane, we have to use the formula:
[tex]\begin{gathered} d\text{ = }\sqrt[]{(x_2-x_1)^2+(y_2-y_1)^2} \\ \text{where (x}_1,y_1)and(x_2,y_2)\text{ are two points} \end{gathered}[/tex]Substituting and simplifying, we have:
[tex]\begin{gathered} d\text{ = }\sqrt[]{(4-(-5))^2+(-3-(-3))^2} \\ d\text{ = }\sqrt[]{9^2\text{ + 0}} \\ d\text{ = 9} \end{gathered}[/tex]Answer : 9 (option A)