00:01
This problem gives us the function f of x equals 3x to the 4th plus 9x squared plus 6 and we want to answer a few questions about it 1, 0s and multiplicity of those zeros.
00:09
Also what the max turning points would be for this function and then we want to confirm all that with the graph.
00:14
So for zeros and multiplicity to find the zeros i'm going to try to factor this expression when it's set equal to 0.
00:20
So we have 3x to the 4 plus 9x squared plus 6 equal to 0.
00:26
So we can factor out a 3 which leaves us with x to the 4th plus 3x squared plus 2 and then to factor this further we can kind of forget about the 3 if we're just finding zeros because it doesn't have an x value with it and when we factor this we can use the same rules that we normally do with the trinomial where we put an x and an x in a front and say what two numbers multiply be the last value in this case 2 and add to be the middle value 3 because this is leading coefficients now 1 the only difference is since this is x to the 4th you need to write x squared in front instead of just x but then you just still ask yourself the same question it's what two numbers, multiple to be two and had to be three.
01:02
And that's a positive two and a positive one.
01:06
And that's as far as you can factor this, because x squared plus two can be factored, and an x squared plus one is not a difference.
01:12
If it was a difference of squares, then we could factor it further, but that's a plus.
01:15
And when we set these equal to zero, to try to find our zeros or x intercepts, the same thing happens for both.
01:24
We get an x squared or x squared equal to negative numbers and square roots of negative numbers are not real zeros, they're imaginary.
01:33
So for the zeros, there are none.
01:38
And if there are no zeros, we don't need to worry about the multiplicity, because the multiplicity would help us to determine the behavior at those zeros...