I do not know how to do all of the following:

1.Point P is the center of one face of a cube and point Q is the center of the opposite face. If the length of the shortest possible path from P to Q along the outer surface of the cube is 2root2 cnetimers what is the volume of the cube in public centimeters.

2. x^2 + 16x + a = (x+b)^2

In the equation above, a and b are constants. If the equation is true for all values of x what is the value of a?

3. In the xy-plane, line m is the reflection of line l across the x-axis. If the intersection of lines l and m is the point (r,s), which of the following must be true?

a) r=0

b) s=0

c) r=s

d) r=-s

e) rs=-1