Find 4B if

I like this question - it is a little different.

Good try guest but I think all the Bs should be on the same side :/

Ax-A+Bx+3B= 1

Bx+3B = 1-Ax+A

B(x+3)=1-Ax+A

4B(x+3)=4(1-Ax+A)

$4B=\frac{4(1-Ax+A)}{x+3}\\$

-4/3(Ax-A+Bx-1) =4B