Find a third-degree polynomial function with real coefficients and with zeros at -4 and -3 5i

If -3+5i is a solution, then by the conjugate root theorem, -3-5i is also a solution. We find the polynomial by multiplying together the factors. If x = -4, then x + 4 is the factor. If x = -3+5i, then (x-(-3+5i)) is a factor, and so is (x-(-3-5i)). Simplifying those down gives us as the first factor as (x+3-5i) and the second as (x+3+5i). We can FOIL those 2 together to get their product, and then FOIL in x+4. FOILing the 2 complex factors together gives us . If we combine like terms and cross out things that cancel it's much easier than what it looks like there! It simplifies down to . Since i^2 = -1, it simplifies further to and finally, to . Now we will FOIL in x+4. . Our final simplified third degree polynomial is

answer is 12345678900987654321234567890987654321

step-by-step explanation: