Answer: The student is not correct
To reflect over the y axis, you use this rule
[tex](x,y) \to (-x,y)[/tex]
The x coordinate swaps in sign (from positive to negative, or vice versa) while the y coordinate stays the same.
So for a point like A(1,1), it should move to A ' (-1, 1) and not (-2,1) like the diagram shows.
B(3,1) should move to B ' (-3, 1)
C(1,4) should move to C ' (-1, 4)
It appears that the student applied a reflection over the y axis, and then they shifted the triangle 1 unit to the left.
