Question

If a polynomial has one root in the form a - √b, it has the second root on the form of a _√b?

Answer 1

The other root would be in the form \[\Large a + \sqrt{b}\]

Answer 2

it's like how the complex roots come in conjugate pairs: a+bi and a-bi

Answer 3

The irrational conjugate roots theorem says:

Let p(x) be any polynomial with rational coefficients. If
a + b*sqrt(c) is a root of p(x), where sqrt(c) is irrational and
a and b are rational, then another root is a - b*sqrt(c).

http://mathforum.org/library/drmath/view/52607.html