How does one know that

4x^2 +3x + 2

has imaginary values for x?

- Jul 1st 2009, 11:43 AMfcabanskiKnowing when the roots of an expression include imaginary values
How does one know that

4x^2 +3x + 2

has imaginary values for x? - Jul 1st 2009, 11:45 AMPlato
$\displaystyle ax^2 +bx+c=0$ has complex (non-real) roots if $\displaystyle b^2-4ac<0$.

- Jul 1st 2009, 12:29 PMfcabanski
Thanks!