Is even function always symmetric about Y-axis? Why? Is y = f (x + 8) even function, and is the graph drawn symmetric about Y-axis?

Is even function always symmetric about Y-axis? Why? Is y = f (x + 8) even function, and is the graph drawn symmetric about Y-axis?


Yes, because the definition of even function is: the domain of definition is symmetric about the origin, and f (- x) = f (x)
Obviously, f (x) is symmetric about the Y axis