Answer:
15
Step-by-step explanation:
we can use the expression
[tex]\sqrt{change in x^{2} +change in y^{2} } =distance between two points[/tex]
[tex]\sqrt{(9-0)^{2}+(6-(-6))^{2} } =\sqrt{9^{2} +12^{2} } \\\\=\sqrt{81+144\\} =\sqrt{225} \\=15 \\\\[/tex]
have a great day.