Question 699415:  write a polynomial function of least degree with integral coefficients having roots ( -4-2i) and -2/3 
 Answer by josgarithmetic(39630)      (Show Source): 
You can  put this solution on YOUR website! Those are two roots.  One of them is a complex root and such type of roots for polynomial functions occur in conjugate pairs.  The required function will have then, three roots:  -4-2i, -4+2i, and -2/3.  The binomials which would match those roots can be (x-(4+2i)), (x-(4-2i)), and (x-(-2/3)).
 
 
Those are equivalent to when multiplied: 
**, 
 
 
If you have no trouble with the multiplication, then I'll leave off the steps.  If my solution was done properly, the (x-(4+2i))*(x-(4-2i)) should be (x^2-8x+20).
 
 
**, In fact, I believe I made a mistake.  Difficult to trace, but the quadratic factor should be  . 
  | 
 
  
 
 |   
 
 |