matlab问题：[x,y,z]=solve('x+y*exp(8.3*z)=0.96','x+y*exp(9.2*z)

matlab问题：[x,y,z]=solve('x+y*exp(8.3*z)=0.96','x+y*exp(9.2*z)=1.56','x+y*exp(9.3*z)=1.48')
其运行结果为x =

1.56 - (0.08*exp(9.2*z2))/(exp(9.2*z2) - 1.0*exp(9.3*z2))


y =

0.08/(exp(9.2*z2) - 1.0*exp(9.3*z2))


z =

z2
请问z2是啥啊?