For the equation 2x^2-5x^3+10=0 find the number the number of complex roots and the possible number of real roots.

2 answers

What I narrowed it to is either. 4 complex roots; 0,2, or 4 real roots. Or 4 complex roots; 1 of 3 real roots
I see only a cubic, which can have only 3 roots.

So, since the complex roots appear in pairs, there are either

1 real and 2 complex, or
3 real

roots. Cubics have a discriminant, just like quadratics, but it's not generally known. As shown here:

http://www.wolframalpha.com/input/?i=2x^2-5x^3%2B10

There is only one real root.