Question 175368
complete: {{{(4x)/((x-1))}}} =  ?/(x+1)(x-1)
:
Cross multiply
?(x-1) = 4x(x+1)(x-1)
:
? = 4x(x+1)
:
so we have:
{{{(4x)/((x-1))}}} =  {{{(4x(x+1))/((x+1)(x-1))}}}