Question 856741
The left member has a negative sign, affecting ALL the parenthesized term within; which is like distributing negative 1.  The reason for the parentheses for the term in the right member is to prevent any confusion in reading the term, which is negative x multiplied by negative y.


You did not say definitely, but you are apparantly trying to simplify the expression shown as the left hand member.  It is not equivalent to either of the other members shown.


This might help, MAYBE.
{{{-(x-y+2z)}}}
{{{-1(x-y+2z)}}}
{{{-1x-(-1)y-(-1)2z}}}
{{{-x+y+2z}}}