Question

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?

Answer 1

A

Answer 2

its A using the discriminant

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

Answer 3

whats radicand anyway??

Answer 4

i go with campbell

Answer 5

the square root symbol

Answer 6

b^2-4ac

Answer 7

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

Answer 8

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.

Answer 9

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

Answer 10

You are correct.

Answer 11

you can substitute each value to find y = 0

or factorise

(2x - 3)(x - 2) = 0

x = 3/2 and 2

Answer 12

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??

Answer 13

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

Answer 14

C is correct.

Answer 15

thanks so much!! :)

Answer 16

No. It's B

Answer 17

Both roots are negative.

Answer 18

B? Really? are you sure?

Answer 19

Okay, i'll trust you! :)

Answer 20

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

Answer 21

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

Answer 22

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

Answer 23

ok

Answer 24

*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

Answer 25

b^2-4ac

Answer 26

is that the answer?

Answer 27

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

Answer 28

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

Answer 29

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

Answer 30

so the answer is b^2-4ac?

Answer 31

I'm still confused... :/

Answer 32

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

Answer 33

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

Answer 34

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

Answer 35

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

Answer 36

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

Answer 37

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

Answer 38

The answer to that is 25

Answer 39

ohhh okay, I understand now

Answer 40

Thank you!!

Answer 41

yw

Answer 42

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