Is x+3 a factor of f(x)=x^4+6x^3+5x^2-15x-2

Is experimental probibilty the same as the observed frequency in math? i need the answer asap!

How many zeros does this polynomial function, y=(x-8)(x+3)^2

The ideal weight of a nickel is 0.176 ounce. to check that there are 40 nickels in a roll, a bank weighs the roll and allows for an error of 0.015 ounce in total weight