Mark H. answered 03/04/21
Tutoring in Math and Science at all levels
First, recognize that there is a factor for each solution (the "zeros"). So the factors are:
x + 2
x + 1 and x - 1, which is the same as x^2 - 1
x - 4
Multiply all these together, and you'll have a 4th-degree polynomial.. Adjust the coefficients as required for the leading coefficient to be equal to 1.