Sagot :
[tex]D:x\neq0\\\\\frac{x-1}{x}=20\ \ \ \ |cross\ multiply\\\\20x=x-1\ \ \ \ |subtract\ x\ from\ both\ sides\\\\19x=-1\ \ \ \ \ \ |divide\ both\ sides\ by\ 19\\\\\boxed{x=-\frac{1}{19}}[/tex]
if (x-1)/(x)=20 then x=