原式=(x-3)²/(x+3)(x-3)+x(x²-4x+4)/x(x+3)
=(x-3)/(x+3)+(x²-4x+4)/(x+3)
=(x-3+x²-4x+4)/(x+3)
=(x²-3x+1)/(x+3)
分解因式(x²-6x+9/x²-9)+(x³-4x²+4x/x²+3x
原式=(x-3)²/(x+3)(x-3)+x(x²-4x+4)/x(x+3)
=(x-3)/(x+3)+(x²-4x+4)/(x+3)
=(x-3+x²-4x+4)/(x+3)
=(x²-3x+1)/(x+3)