00:01
This problem wants us to determine what the polynomial or the polynomial function would be with the given characteristics of the y intercept being 018.
00:08
We have 2x intercepts of 3 .0 and negative 30.
00:11
We want the degree to be 2.
00:13
And we also want the end behavior to be correct where as x approaches infinity, in other words it goes to the right.
00:18
F of x, the y values go to negative infinity.
00:20
And the same thing as x approaches negative infinity or goes to the left, we want the y values to also approach negative infinity.
00:26
So we both, basically want both end behaviors to be falling on both ends or going down.
00:30
So to start, we're going to focus on the x intercepts to start building the polynomial because a 3 -0 solution would come from x minus 3 as a binomial, and negative 3 -0 as a solution would come from x plus 3 as a binomial.
00:44
So when we multiply these together, we get x squared plus 3x minus 3x, and negative 3 times negative 3, or negative 3 times positive 3 is negative 9.
00:55
So 3x minus 3x will eliminate, and we have x squared minus 9.
01:00
So this would be a function that is true for the x intercept so far at 30, negative 3 .0.
01:07
But one thing we need to worry about is what the y intercept is supposed to be.
01:10
We are supposed to be able to plug in 0 for x, and the result is supposed to be 18 after we evaluate.
01:17
But what happens when we plug in 0 for x is we get 0 squared, which is just 0, and 0 minus 9 is negative 9...