In this question, the highest power is x^4 which is an even number. In this case, the f(x) will be same for plus X or minus X.
The coefficient is -8 which is a minus. In this case, the f(x) will become minus:
The result would be:
when X go the left end(X= -∞), the f(x) will become minus (f(x)→−∞)
f(x)→−∞, as x→−∞
when X go the right end(X= +∞), the f(x) will become minus (f(x)→−∞)
f(x)→−∞, as x→+∞
