Math CentralQuandaries & Queries


Question from Lan, a student:

If b and c are real numbers so that the polynomial (x^2) + bx + c has 1 + i as a zero, find b + c.

Hi Lan,

Since your polynomial x2 + bx + c has real coefficients and 1 + i is a root then 1 - i is a root also. Substitute 1 + i and 1 - i into the equation x2 + bx + c = 0 and you will obtain two equations in b and c which you can solve for b and c. Once you have numeric values for b and c you can use the quadratic formula to find the root of x2 + bx + c and hence verify your solution.


About Math Central


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.
Quandaries & Queries page Home page University of Regina PIMS