Answer: Y-axis.
Step-by-step explanation:
Given : On a coordinate plane, a triangle has points J (negative 3, 9), L (negative 3, 2), and K (5, 2).
After reflection the coordinates of point K' = (-5 , 2)
Here the sign of x-coordinate changed from K to K' but the y-coordinated remained exactly same.
We know that when we reflect a figure across y-axis the sign of x-coordinate changes but y-coordinate remains same.
Rule for reflection across y-axis = (x,y) → (-x , y)
∴ The line of reflection maps point K to point K' at (–5, 2) = Y-axis.
