Question 1177406
WHAT are you trying to do?  What QUESTION do you hope to answer?  Are you looking for solution for the system?


{{{system((x-1)^2+(y+1)^2 = 50,-x+y = -10)}}}



The negative 1 coefficient on x in the second equation should be no trouble - none.


{{{-x+y=-10}}}
{{{y=x-10}}}
-
SUBSTITUTE:
{{{(x-1)^2+(x-10+1)^2=50}}}
{{{(x-1)^2+(x-9)^2=50}}}

{{{x^2-2x+1+x^2-18x+81-50=0}}}



Can you continue from here, solve for x, and then continue on?