The Points are in the form (x,y), and they are A(-3,8) and B(5,-4).
The length between two points is:
[tex]\sqrt[]{(x_1-x_2)^2+(y_1-y_2)^2}[/tex]In this case:
[tex]\text{length = }\sqrt[]{(-3-5)^2+(8-(-4))^2}=\sqrt[]{(-8)^2+(12)^2}=\sqrt[]{64+144}[/tex][tex]\text{length =}\sqrt[]{208}\text{ = }\sqrt[]{16\cdot13}=4\sqrt[]{13}[/tex]The correct anser is:
[tex]\text{length = 4}\sqrt[]{13}[/tex]