Answer:
1)the x-axis
2) when reflecting a shape over the x-axis the x coordinate stays the same and the y-coordinate becomes the opposite, so positive numbers become negative numbers and negative numbers become positive
Explanation:
the rule of reflecting over the x-axis is (x, y)->(x, -y)
m=(-5,4)->(-5,-4)
n=(-2,3)->(-2,-3)
l=(-4,2)->(-4,-2)