Multiplying imagionary roots of a polynomial I am trying to answer the following question: > The roots of the quadratic equation $ax^2-16x+25$ are $2+mi$ and $2-mi$, where $m>0$. Compute the sum of $a+m$. Should the zeros of the equation be $x-(2+mi)$ and $x-(2-mi)$ or $x-2+mi$ and $x-2-mi$, or maybe something else? I really have no idea.

The roots are given by the quadratic formula: $$x = \frac{16\pm \sqrt{16^2 - 4*25*a}}{2a}$$

We know that the real part of the roots will be $2$, so $\frac{16}{2a} = 2$, and $a = 4$. So we can plug that back into the quadratic formula. $$x = \frac{16\pm \sqrt{16^2 - 4*25*4}}{2*4}$$ and solve for your roots.

That should be more than enough to get you started.