50 points will mark brainliest Is this a function or not a function? is this linear or non linear

The graph of the the function f(x) is given below. find [tex]\lim_{x \to 0\zero} f(x)[/tex] [tex]\lim_{x \to 1+\oneplus} f(x)[/tex] [tex]\lim_{x \to 0-\zeroneg} f(x)[/tex]