How can you tell when a quadratic equation has no real solutions?
A. when the radicand is negative
B. when b in the quadratic formula is greater than the radicand
C. when the radicand equals zero
D. when the radicand is not a perfect square
I believe the answer is A? is that right?

- anonymous

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- Mertsj

A

- campbell_st

its A using the discriminant
\[b^2 - 4ac\] < 0 no real solutions the radical will be negative

- experimentX

whats radicand anyway??

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## More answers

- experimentX

i go with campbell

- campbell_st

the square root symbol

- Mertsj

b^2-4ac

- Mertsj

\[x=\frac{-b \pm \sqrt{b^2-4ac}}{2a}\]

- anonymous

Thanks!! :) I also have this one...
For which value of x does the graph of y = 2x2 − 7x + 6 cross the x-axis?
A. −3/2
B. −2/3
C. 2
D. 3
I think its C.

- Mertsj

\[b^2-4ac\] is the discriminant

- Mertsj

You are correct.

- campbell_st

you can substitute each value to find y = 0
or factorise
(2x - 3)(x - 2) = 0
x = 3/2 and 2

- anonymous

Thanks so much, here's another one i'm stuck on...
What are the approximate solutions of 4x2 + 3 = −12x to the nearest hundredth?
A. x ≈ −3.23 and x ≈ 0.23
B. x ≈ −2.72 and x ≈ −0.28
C. x ≈ 0.28 and x ≈ 2.72
D. x ≈ −0.23 and x ≈ 3.23
I think its C, but I'm not sure??

- campbell_st

put it in standard form
4x^2 + 12x + 3 = 0
use the general quadratic formula
\[x = (-b \pm \sqrt{b^2 - 4ac})/2a\]
in your question a = 4, b = 12 and c = 3

- Mertsj

C is correct.

- anonymous

thanks so much!! :)

- Mertsj

No. It's B

- Mertsj

Both roots are negative.

- anonymous

B? Really? are you sure?

- anonymous

Okay, i'll trust you! :)

- Mertsj

\[x=\frac{-12\pm \sqrt{96}}{8}\]

- anonymous

I have one more question that's really confusing me, would you mind sticking around for one more?

- Mertsj

\[x=\frac{-12+9.80}{8} or x=\frac{-12-9.80}{8}\]

- Mertsj

ok

- anonymous

*note* don't ask me why the numbers are spreed out like that, I just copied and pasted it onto here, that how it looks on my paper.
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

- Mertsj

b^2-4ac

- anonymous

is that the answer?

- Mertsj

Well which part would you choose? -b? 2a????

- Mertsj

\[b^2-4ac=7^2-4(2)(3)=49-24=25\]

- anonymous

I don't know... This is really confusing me for some reason...

- anonymous

so the answer is b^2-4ac?

- anonymous

I'm still confused... :/

- anonymous

or is the answer this: b² - 4ac = (7)² - 4(2)(3) = 49 - 24 = 25.

- Mertsj

The discriminant, which is b^2-4ac, is the part of the quadratic formula which tells you about the roots.

- Mertsj

Do you understand that the question has two parts? READ THE QUESTION!!!

- Mertsj

PART 1: Which part of the quadratic formula tells you whether the quadratic equation can be solved by factoring?

- Mertsj

The answer to that is :b^2-4ac

- Mertsj

PART 2: Use the part of the quadratic formula that you chose above and find its value given the following quadratic equation:
2x2 + 7x + 3 = 0

- Mertsj

The answer to that is 25

- anonymous

ohhh okay, I understand now

- anonymous

Thank you!!

- Mertsj

yw

- anonymous

I just wasn't looking at the problem correctly, sorry for the confusion and thanks again for breaking it down for me

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