(x-xo)² + (y-yo)² = R²
(x-1)² + (y-0)² = 4
x²-2x+1 + y² = 4
x²+y²-2x-3 = 0
(6b-9)(9b+6)-9b(6b+9)=
54b²+36b-81b-54-54b²-81b=
36b-54=
(36*5,3)-54=
190,8-54=
136,8