Answer
$y=-x+3$
$6\sqrt 2$
$(1,2)$
Work Step by Step
1. Find the slope $m=\frac{-1-5}{4+2}=-1$, thus the equation is $y+1=-(x-4)$ or $y=-x+3$
2. The distance between the two points $d=\sqrt {(4+2)^2+(-1-5)^2}=\sqrt {72}=6\sqrt 2$
3. We can find the midpoint $(\frac{4-2}{2},\frac{5-1}{2})$ or $(1,2)$
