有没有问题？

Solve: (1+b)/(b+1) =2

1+b= 2b +2   ......(*)

b= 2b +1

b^2 = 4b^2 +4b +1

0 = 3b^2+4b+1

0=3b^2+3b+b+1

0=3b(b+1)+(b+1)

0=(3b+1)(b+1)

b = -1/3   or  b = -1 , not acceptable because of ( *)