A small pouch contains 8 black marbles, 6 white marbles, and 12 red marbles Find the probability of picking a red then a black marble if you do not replace the first Marble

Write a polynomial function f of least degree that has rational coefficients, a leading coefficient of 1, and the given zeros. 3, 4+2i, 1+(sqrt)7 the answer is supposed to be: f(x)=x(^5)-13x(^4)+60x(^3)-82x(^2)- 144x+360 what am i doing wrong?