Question 1139878
Reflect this triangle over the line {{{y=-x}}}

Point {{{A}}}({{{2}}},{{{1}}})  
Point {{{B}}}({{{2}}},{{{3}}})  
Point {{{C}}}({{{3}}},{{{1}}})


{{{drawing( 600, 600, -10, 10, -10, 10, 
circle(2,1,.12),circle(2,3,.12),circle(3,1,.12),
locate(2,1,A),locate(2,3,B),locate(3,1,C),
line(2,1,2,3),line(2,1,3,1),line(3,1,2,3),
  graph( 600, 600, -10, 10, -10, 10, -x,-x)) }}}

 If you reflect over the line {{{y = -x}}}, the {{{x}}}-coordinate and{{{ y}}}-coordinate change places and are negated (the signs are changed).


Point {{{A[1]}}}({{{-1}}},{{{-2}}})  
Point {{{B[1]}}}({{{-3}}},{{{-2}}})  
Point {{{C[1]}}}({{{-1}}},{{{-3}}})


{{{drawing( 600, 600, -10, 10, -10, 10, 
circle(2,1,.12),circle(2,3,.12),circle(3,1,.12),
locate(2,1,A),locate(2,3,B),locate(3,1,C),
line(2,1,2,3),line(2,1,3,1),line(3,1,2,3),

circle(-1,-2,.12),circle(-3,-2,.12),circle(-1,-3,.12),
locate(-1,-2,A1),locate(-3,-2,B1),locate(-1,-3,C1),
line(-1,-2,-3,-2),line(-1,-2,-1,-3),line(-1,-3,-3,-2),

  graph( 600, 600, -10, 10, -10, 10, -x,-x)) }}}