Will mark brainly! :)

Answer:
Y = 0
Step-by-step explanation:
Both functions have
maximum of [tex]\frac{2}{3}[/tex]
minimum of - [tex]\frac{2}{3}[/tex]
midline is then the average of these
([tex]\frac{2}{3}[/tex] - [tex]\frac{2}{3}[/tex] ) ÷ 2 = 0 ÷ 2 = 0
midline has equation y = 0 ( that is the x- axis )