Tetrahedron - its the only one that has a base from which all edges meet at a single point.
The given function is

The inverse function is

To get the inverse, we swap each x and y coordinate.
The rule is 
So that's why the point (0,1) becomes (1,0) for instance.
Answer:
(x,y)=(-2,-5)
Step-by-step explanation:
y=1/2x-4
y=-2x-9
(y=) 1/2x-4=-2x-9
1/2x +2x=-9+4
1/2x +4/2x=-5
5/2x=-5
5x=-5*2
5x=-10
x=-2
x=-2
y=-2x-9=-2*(-2)-9=4-9=-5
(x,y)=(-2,-5)