（2x-6/x²-6x+9）+1=x²-4/x²-4x+4
2(x-3)/(x-3)² +1=(x+2)(x-2)/(x-2)²
2/(x-3) +1 =(x+2)/(x-2)
(x-1)/(x-3)=(x+2)/(x-2)
(x-1)(x-2)=(x-3)(x+2)
x²-3x+2=x²-x-6
2x=8
x=4