Question

How does x/(x+1) = 1-1/(x+1)

Answer 1

Do you know about LCM or LCD ???

Answer 2

you can split up the numerator \[\implies \frac{x+1 - 1}{x+1}\]
now split up the fraction
\[\implies \frac{x+1}{x+1} - \frac{1}{x+1}\]
does that give you a hint?