What you ask is not possible. , but that is a complex root. Complex roots ALWAYS come in conjugate pairs, but you have already provided a root that is not complex and the Fundamental Theorem of Algebra says exactly two roots to a quadratic. Now if what you ACTUALLY meant was solutions of and (VERY different from what you asked) then proceed as follows:
Multiply the two binomials. Hint: They are a conjugate pair, so the result is the difference of two squares.
My calculator said it, I believe it, that settles it