Question

Use the quadratic formula to solve the equation.

-5x^2 - 14x + 3 = 0

Select the correct choice below and, if necessary, fill in the answer box to complete your choice.

A. x =?
B. The solution is not a real number.

Answer 1

Any ideas? x3

Answer 2

not really :/

Answer 3

Is this all of the question? A is x=?

Answer 4

yes

Answer 5

im unsure?...what happened?

Answer 6

Hey, @Ms-Brains, note that he was instructedto use the quadratic formula here.

Answer 7

qwertyking: I'd suggest you look up and copy down the quadratic formula. You will likely need this formula again and again.

Next, take a look at the given polynomial (a quadratic): -5x^2 - 14x + 3 = 0. It has three coefficients, which here happen to be -5, -14 and 3.

We label these a=-5, b=-14, and c=3.

Substitute these values into the quadratic formual (which you have already looked up and copied down for reference).

simplify your results. x=?? (there must be TWO roots / solutions / zeros).

Answer 8

what do you mean @mjdennis ?

Answer 9

I know the quadratic formula already.

Answer 10

Great. type it in here, please.

x= ?

Answer 11

x = -b + or 1 the square root of the discrimant (b^2 - 4ac)....all of this over 2a

Answer 12

I mean + or -

Answer 13

x = -b plus or minus the square root of the discrimant (b^2 - 4ac)....all of this over 2a

Good. Now, b=-14, so, after substitution, you get:

x = -[-14] plus or minus the square root of the discriminant ( [-14]^2 - 4ac)....all of this over 2a.

We still have to insert the known values of a and c.

But first, simplify this:

x = -[-14] plus or minus the square root of the discriminant ( [-14]^2 - 4ac)....all of this over 2a.

Answer 14

okay so -14 squared is -196. So we are looking for -196 - 4ac over 2a....

Answer 15

Not quite. -14 squared is (-14)^2 = ? Those parentheses are mandatory.

What about the "-b" part of the quadratic equation? Please be certain to include it.

Answer 16

woops postive 196

Answer 17

Yes, and so \[x=\frac{ -(-14)\pm \sqrt{196-4(a)(c)} }{ 2(-5) }\]

Answer 18

What next? You must insert the proper values of a and c.

Answer 19

now how do I find that?

Answer 20

a=-5, so merely substitute (-5) for a; c=3, so subst. (3) for c.

Answer 21

how did you know?

Answer 22

You must follow the quadratic formula as tho' it were a road map. The values of a, b and c come from the given quadratic equation, y=-5x^2-14x+3.

Answer 23

As before, a=-5, b=-14, c=3.

Answer 24

Substituting c=3, we get:\[x=\frac{ -(-14)\pm \sqrt{196-4(a)(3)} }{ 2(-5) }\]

Answer 25

Finally, where you see (a), substitute (-5).

Answer 26

Please share everything you do from this point on.

Answer 27

what about the a next to the 4?

Answer 28

that's the "a" I was talking about. Replace that (a) with (-5) now, please.