y axis reflected, just imagine it
means all x values are going to turn negative
initial values:
A=(1,3)
B=(4,5)
C=(3,1)
reflected
A'=(-1,3)
B'=(-4,5)
C'=(-3,1)
A.
the reflected coordinates are A'=(-1,3), B'=(-4,5), C'=(-3,1)
B. the x coordinates flip flopped, they turned negative, y coordinates stayed the same