Answer:
The zeros are -6, -4, 3 and 4
Step-by-step explanation:
In order to find the zeros of a function we have to:
- Set the function equal to 0
- Factor it
- Set each one of the factors equal to 0
- Solve for x for each one of those factors.
Finding the zeros.
We can start setting the function equal to 0

For this exercise we have

Then we can factor each parenthesis.
For the first one we have a difference of squares, so we can use
, which will give us

For the last parenthesis, we need to think of a couple of numbers that multiplied give us the last number which is -18 and the sum give us the middle coefficient which is +3, those numbers are +6 and -3, since +6*(-3) = -18 and their sum give us 3.

Then we can set each one of those factors equal to 0.

So we can solve for x for each, which will give us

Thus the zeros are -6, -4, 3, 4.
And we can plot them as you can see on the attached image, just click on dots and select (-6,0), (-4,0), (3,0) and (4,0). The sketch will look like the following image.