Answer:
(-6,-4)
Step-by-step explanation:
Rule for reflection over the y axis (x,y) -----> (-x,y)
Explanation of rule : change the sign of the x value and keep the y value the same.
Applying rule to given coordinate
(6,-4) -----> change the sign of 6 to get -6 and keep -4 as it is -----> (-6,-4)
Refer to the attached image for more validation. Note that x=0 is the y axis