How do you determine whether x+2 is a factor of the polynomial #3x^4+5x^3+x-2#?
Have you ever done long or synthetic division? Both are good options, but difficult to "type" an answer to demonstrate.
Another great option would be to evaluate f(-2):
Since the answer is 4, that means there would be a remainder of 4 when we would divide the polynomial by x+ 2. It is not a factor.