The answer is the answer is C and F.
This is found by inserting the equation above into the quadratic formula or -b plus or minus the square root of b^2 - 4ac over 2a.
With that, you find that the first number is a -3, which eliminates choices B and D.
Then, solving the 4ac portion, you find that inside the square root the number is 29, which gives you the last two answer choices.
Hope this helps!
One reason that negative numbers would not make sense for values of the variables is that the solution having a negative value is not valid. It might be that the expression represents a real word problem and a negative value will not make any sense. Hope this helps.
The answer is D. The answer is D because you just keep multiplying each number by the same number.
6 • 8 = 48
7 • 8 = 56