8 x 2 + 6x + 5=0
16 + 6x + 5=0
6x+21=0
6x+21-21=0-21
6x=-21
6x/6=-21/6
x=-7/2
The answer to your question is 210 combinations are possible :)
Basically you need to find the answer choice that is rational. That way the sum will also be rational.
√7 is irrational as well as π and 0.5050050005...
2/4 is the only rational option.
answer: D