# Thread: quadratic homework help

1. ## quadratic homework help

Hi all can you help, I have been asked to give answer in decimal to a quadratic formula. I have attached my workings, but Im not sure if my answers are correct, If I have made and error, can I get a pointer as to what I have done wrong...Many thanks.

2. ## Re: quadratic homework help

(11 + root97) / 2 = 10.4244289

(11 - root97) / 2 = 0.5755710991

3. ## Re: quadratic homework help

thanks for the reply, I have just done it all again and the scientific calculator is giving me my origional answer,but a standard calculator give me your answers? lost
Dave

4. ## Re: quadratic homework help

Originally Posted by davellew69
thanks for the reply, I have just done it all again and the scientific calculator is giving me my origional answer,.....
Well, you're not "feeding it" properly then: the FULL [-b +- SQRT(b^2 - 4ac)] has to be divided by (2ac);
you're going: -b +-[SQRT(b^2 - 4ac)]/(2ac) ; OK?

5. ## Re: quadratic homework help

same answer as I get the first time

6. ## Re: quadratic homework help

@wilma

just 2a

@OP degrees mode calculator?

7. ## Re: quadratic homework help

I see what you've done wrong here...

You've put 11+ on its own so you're doing 11 +- (root97 / 2)

What you want to do is (11+- root97) / 2

8. ## Re: quadratic homework help

you have lost me vince

9. ## Re: quadratic homework help

What you did:

What you should have done:

The 11+ or - goes within the divide by 2 part, which you put outside of it.

10. ## Re: quadratic homework help

why do i do it that way?

11. ## Re: quadratic homework help

lol got it...now I see why the brackets are used that way on a scientific calculator, thanks so much for your help..top fella, many thanks

Dave
( I may get got at this one day lol)

12. ## Re: quadratic homework help

If you have a scientific calculator:

fraction button -> 11 +- square root 97 -> down button -> 2

Natural display calculators mean you don't need the brackets on the calculator.

If you need more help just PM me here and it'll give me an email.

13. ## Re: quadratic homework help

C'mon Dave...relax...:
4 + 10/2 = 9
(4 + 10)/2 = 7

Get it?