（x+6/x+1）-（3x平方+10x+4/x平方+3x+2）+（2x+1/x+2）=0
[(x+6))(x+2)+(2x+1)(x+1)]/(x^2+3x+2)-(3x平方+10x+4/x平方+3x+2)=0
(3x^2+11x+13)/(x^2+3x+2)-(3x^2+10x+4)/(x^2+3x+2)=0
(x+9)/(x^2+3x+2)=0
x+9=0
x=-9