Decide 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:

4x2 + 6x + 2 = 0

Question

Decide 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:

4x2 + 6x + 2 = 0

afloridagirl · Answer

im not sure what this is even asking..

afloridagirl · Answer

@jim_thompson5910

jim_thompson5910 · Answer

have you learned about the term discriminant? http://www.regentsprep.org/regents/math/algtrig/ate3/discriminant.htm

afloridagirl · Answer

a little bit

afloridagirl · Answer

b2 − 4ac

afloridagirl · Answer

i think it was that one but i wanna make sure..

jim_thompson5910 · Answer

on that page, it says 

`If the discriminant is a perfect square, the two roots are rational numbers.`

which is another way of saying "if the discriminant is a perfect square, then we can factor the quadratic in terms of whole numbers"

jim_thompson5910 · Answer

In the case of 4x^2 + 6x + 2 we have 

a = 4
b = 6
c = 2

plug those values into b^2 - 4ac and tell me what result you get.

afloridagirl · Answer

4x^2 + 6x + 2 = 0
4x^2 + 4x + 2x + 2 = 0
4x(x + 1) + 2(x + 1) = 0
(4x + 2)(x + 1) = 0

afloridagirl · Answer

is that right?

afloridagirl · Answer

@jim_thompson5910

jim_thompson5910 · Answer

They don't want you to factor. They just want the value of the discriminant.

afloridagirl · Answer

???

jim_thompson5910 · Answer

`Use the part of the quadratic formula that you chose above and find its value,`
they want the value of $\Large \color{red}{b^2 - 4ac}$

jim_thompson5910 · Answer

a = 4
b = 6
c = 2

$$\Large b^2 - 4ac = 6^2-4*4*2 = ???$$

afloridagirl · Answer

4?

jim_thompson5910 · Answer

yes

jim_thompson5910 · Answer

extra info: since the discriminant (4) is a perfect square, this means we can factor 4x^2+6x+2 over the whole numbers. You've just shown that above. You didn't need to factor, but it's good practice to factor so it doesn't hurt.

jim_thompson5910 · Answer

So as you can guess, the discriminant helps save you a lot of time if you're given something 20x^2 + 15x - 29 which isn't clear if it can be factored or not.

afloridagirl · Answer

so 4 is the answer?

jim_thompson5910 · Answer

There are 2 answers they want here. The first part would be b^2-4ac. The second part would be 4.

jim_thompson5910 · Answer

The two are very similar and linked together

afloridagirl · Answer

so how do i put that?

jim_thompson5910 · Answer

What do you mean?

afloridagirl · Answer

Decide 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:

4x2 + 6x + 2 = 0

Numerical Answers Expected!

afloridagirl · Answer

i have to type it in

jim_thompson5910 · Answer

So it sounds like they just want you to type in a single number

jim_thompson5910 · Answer

based on the statement `Numerical Answers Expected!`

jim_thompson5910 · Answer

I thought it wanted you to pick from $\Large -b$ or $\Large b^2 - 4ac$ or $\Large 2a$ but I guess they don't want that as part of the answer.

afloridagirl · Answer

thats why i said i didnt know what to do

jim_thompson5910 · Answer

if it were me, I'd just type in the single number result you got

jim_thompson5910 · Answer

it sounds like that's all they want to know

afloridagirl · Answer

okay i will try that