solve((b2/b1)*t=b2/((b1-c)*(x-c),x)
solve((b2/b1)*t=b2/(b1-c)*(x-c),x)
simplify(solve((b2/b1)*t=b2/(b1-c)*(x-c),x))
simplify(x)
solve(b2*t/b1=c*(b1-t)/b1,t)