5M+12X=1/2+X
11X=1/2-5M
X=[0.5-5M]/11
X[M+1]=M[1+X]
XM+X=M+MX
X=M
所以:[0.5-5M]/11=M+2
0.5-5M=11M+22
16M=-21.5
M=-43/32