Answer:
8 units is the answer.
Step-by-step explanation:
Pythagorean theorem can be written as,
[tex]d=\sqrt{(x_2-x_1)^2 + (y_2-y_1)^2} \\\\d=\sqrt{(9-9)^2 + (-7-1)^2}\\\\d=\sqrt{(0\\)^2+(-8)^2} \\\\d=\sqrt{64} \\\\d=8[/tex]
∴ d = 8 units
