### Home > A2C > Chapter Ch9 > Lesson 9.3.2 > Problem 9-148

9-148.

Use the three roots to find the individual polynomials that make up the cubic equation.

(*x* + 1)(*x* + 2 + 5*i*)(*x* + 2 − 5*i*)

Now multiply the two complex polynomials.

(*x* + 2 + 5*i*)(*x* + 2 − 5*i*) = *x*^{2} + 4*x* + 29

Now multiply this equation by *x* + 1.

(*x* + 1)(*x*^{2} + 4*x* + 29)

*x*^{3} + 5*x*^{2} + 33*x* + 29