? idont understsnd be more specific
Step-by-step explanation:
Decimal system, also called Hindu-Arabic number system or Arabic number system, in mathematics, positional numeral system employing 10 as the base and requiring 10 different numerals, the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
Using the quadratic equation we get:

Factoring out 2 we get

Factoring out the imaginary number:

So b.