You can put this solution on YOUR website! first off... find a number that makes the function zero. I am assuming that there is a nice number (ie an integer) since they have asked you to do this question... horrible number would make it virtually impossible to do.
Looking at the function:
to make this zero by using a positive number will not work --> the cube will get bigger and bigger and the only negative term is the x.
So we need to think about a -ve number since the cube of a negative number is still -ve.
Start with x=-1 and this is too small a number
x=-2 and x=-3 still too small
x=-4 gives:
-64 + 64
0
so x=-4 is one root --> (x+4) is a factor.
You now need to divide the function by this to find the other factor and then that quadratic should factorise too, to give you nice answers like (x+4).
