M=(x^2-2x+4)/(x^2-3x+3)
x^2-2x+4=Mx^2-3Mx+3M
(1-M)x^2+(3M-2)x+4-3M=0
△=(3M-2)^2-4(1-M)(4-3M)≥0
9M^2-12M+4-12M^2+28M-16≥0
-3M^2+16M-12≥0
3M^2-16M+12≤0
(8-3√2)/3≤M≤(8+3√2)/3
所以M=2或3或4
M=2时,-x^2+4x-2=0,
M=3时,-2x^2+7x-5=0
M=4时,-3x^2+10x-8=0
因为三种情况下的6个x值各不相同
所以一共有6个x能使M为整数.