One root of a quadratic with real coefficients is 2 + i*3*sqrt(5). Find the quadratic.
Imaginary roots come in + - p airs the other root is 2 - 3 sqrt5 i
(x - 2 - i 3 sqrt5)(x-2+i 3 sqrt 5 ) Multiply this all out to get:
= x^2 -4x+49