Answer :
[tex]\begin{gathered} \text{Distance betw}een\text{ two points, d =}\sqrt{\text{ }(y_2-y_1)^2+(x_2-x_1)^2} \\ x_1=-1,y_1=3,x_2=-9,y_2=3 \\ \\ d\text{ = }\sqrt[]{(3-3)^2+(-9-(-1))^2} \\ d=\text{ }\sqrt[]{0^2+(-9+1)^2} \\ d=\text{ }\sqrt[]{(-8)^2} \\ d=\sqrt[]{64} \\ d=8 \end{gathered}[/tex]
The required distance is 8 units