Question 43446
(1/x-1/b)/(1/xb+1/2)=
(b-x)/xb/(2/2xb+xb/2xb)=(b-x)/xb)((2+xb?)/2xb=
(b-x)/xb. 2xb/(2+xb)=(b-x).2(2+xb)=2(2+xb)(b-x)