Which part of the quadratic formula tells you whether the quadratic equation can be solved by factoring?

−b b2 − 4ac 2a

Use the part of the quadratic formula that you chose above and find its value given the following quadratic equation:

2x2 + 7x + 3 = 0

Question

Which part of the quadratic formula tells you whether the quadratic equation can be solved by factoring?

            −b             b2 − 4ac            2a

Use the part of the quadratic formula that you chose above and find its value given the following quadratic equation:

2x2 + 7x + 3 = 0

anonymous · Answer

what is under the radical sign, b^2 - 4ac, it's called the discriminant

anonymous · Answer

What radical sign? I don't see one...

anonymous · Answer

What is the final answer? I don't get it...

anonymous · Answer

i mean, in the actual quadratic formula, what is under the radical sign is what you would use.

b^2 - 4ac (this is underneath a square root sign in the quadratic formula)

in your question, 2x2 + 7x + 3 = 0 

b = 7, a = 2, and c = 3

all it is is a matter of plugging in the variables and finding the answer.

the point of using the discriminant is to see whether the quadratic formula can be used or not - remember, the discriminant is underneath a radical sign, so if the discriminant is less than 0, you can't use the quadratic formula (you can't take the square root of a negative number). If the discriminant = 0, I believe there is only 1 root (or answer), and if the discriminant is > 0, there will be 2 roots (or answers).

anonymous · Answer

I think they are waiting for an answer like
$$
b^2 - 4a c
$$
must be a perfect square to be able to factor using only rational numbers.