Question

using the quadratic formula solve each equation. give two forms of each solution an expressionwith radical and a calculator approximation rounded off to two decimal places. 2x^2+3x-4=0.

Answer 1

What part of this problem do you need help with?

Answer 2

the first part

Answer 3

Ive not done these before

Answer 4

do you know the quadratic equation?

Answer 5

Yes

Answer 6

so for any 2nd degree polynomial ax^2 + bx +c = 0
In your case a=2, b=3, and c = -4

Answer 7

(-b +- sqrt(b^2-4ac))/2a

Answer 8

its basically plug and chug

Answer 9

try putting the values of a, b, and c into the quad equation and tell me what you get
or at least let me see the substitution and then Ill help you simplify if needed

Answer 10

-3+-Sqrt3^2-3(2)(-4)

Answer 11

this is as far as i have gotten

Answer 12

/3 (?)

Answer 13

cool deal! So lets go ahead and make the 3^2 into 9, and that -3(2)(-4) into +24
So youve got -3 +- sqrt(23) all over 4. I think that's about as far as you can take it, considering that 23 is prime

Answer 14

Do you know how to put that into your calc to get an estimate?

Answer 15

I don't know I will try

Answer 16

how do you do the plus or minus on it ?

Answer 17

You just have to do it twice, once with plus and once with minues

Answer 18

oh ok

Answer 19

ok I got 2.74456

Answer 20

for the + or the -?

Answer 21

so basically, when you are solving a quadratic equation, you are finding the x values for which y = 0

Answer 22

that is +

Answer 23

ok then cool so you understand that quadratic equations have 2 solutions?

Answer 24

do I do the sqrt of 23 or the whole equation?

Answer 25

Then with the - I got -17.2336...

Answer 26

the sqrt of 23 only

Answer 27

oh did not know that thanks

Answer 28

it should be (3/4) - sqrt(23)/4

dont forget the /2a on the bottom

Answer 29

right

Answer 30

ok this is what i got -3sqrt 23/4=-.6020, then -3 - sqrt23-4= -5.3979

Answer 31

the first one is + sorry

Answer 32

shouldn't the sqrt be 33?

Answer 33

probably lol. I'm sleepy. Make sure you divide by 4? the - one you just did looks a lil low. I think im going to go to bed, I have an 8am class tommorrow

Answer 34

ok good night thanks for helping me your awsome