a^2（x-2）-3a=x+1
a^2x-x=2a^2+3a+1
(a^2-1)x=(2a+1)(a+1)
x=(2a+1)(a+1)/(a+1)(a-1)
x=(2a+1)/(a-1)
ax+b-(3x+2ab)/3=0.5
ax-x=0.5-b+2/3ab
x=(0.5-b+2/3ab)/(a-1)