Steps:
1) Draw the circle and mark the center (A) and the given point (B)
2) Draw a line that passes through the center (A) and the given poiint (B).
3) Draw a perpendicular line to the segment AB.
The last line drawn is tangent to the circle at the given point.
We can solve this using substitution.
because x-y=2.5
x=y+2.5
Now substitute x into other equation.
2(y+2.5)^2-2y=125
2y^2+10y+12.5-2y=125
2y^2+8y-112.5=0
Now comes the ugly part
y=-4+-sqrt(16+900)
y=-4+-sqrt916
y=-4+-2sqrt229
x=-1.5+-2sqrt229