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Mathematics 7 Online
OpenStudy (secret-ninja):

Am I right? Question is in comments.

OpenStudy (secret-ninja):

OpenStudy (anonymous):

bring across the 8

OpenStudy (anonymous):

you get 2x^2 #+9x-8=0

OpenStudy (anonymous):

think @Secret-Ninja ninja can solve from there!

OpenStudy (secret-ninja):

\[My~Work: \] \[2x^2+9x=8 ~~~ turns~into~~~~~ 2x^2+9x-8=0\] \[x= \frac{ 9\pm \sqrt{9^2-4(2)(8)} }{ 2(2) }\] \[x=\frac{ 9\pm \sqrt{81-64} }{ 2(2) }\] \[x=\frac{ 9\pm \sqrt{17} }{ 4 }\] \[x=\frac{ 9+4.1231 }{ 4 } ~~~~~~~~~~~~~~~~~~ x=\frac{ 9-4.1231 }{ 4 }\] \[x=\frac{ 13.1231 }{ 4 } ~~~~~~~~~~~~~~~~~~~~~~ x=\frac{ 4.8769 }{ 4 }\] \[x = 3.280775~~~~~~~~~~~~~~~~~~~~~~~x=1.219225 \]

OpenStudy (secret-ninja):

The closest answer to my work was Choice C.

OpenStudy (secret-ninja):

@KamiBug

OpenStudy (secret-ninja):

Sorry, those 9's were supposed to be negative, but you get the idea.

OpenStudy (secret-ninja):

:p

OpenStudy (anonymous):

I think @Secret-Ninja work is correct

OpenStudy (anonymous):

pwerhaps there is a difference in round-off?

OpenStudy (secret-ninja):

D: I got it wrong. :O :[

OpenStudy (anonymous):

can you show the the answers you were given?

OpenStudy (freckles):

you put in -c instead of c

OpenStudy (freckles):

\[2x^2+9x-8=0 \\ x=\frac{-9 \pm \sqrt{9^2-4(2)(-8)}}{2(2)}\] do you see what I mean?

OpenStudy (freckles):

\[x=\frac{-9 \pm \sqrt{81+64}}{4} \\ x=\frac{-9 \pm \sqrt{145}}{4}\]

OpenStudy (anonymous):

Freckles seems to have this

OpenStudy (secret-ninja):

*facepalm* I sometimes just feel so stupid >.<

OpenStudy (anonymous):

Stop that @Secret-Ninja , the no.1 idea you have to keep in your head is "confidence"!

OpenStudy (loser66):

Ninjia work: \(\huge x= \frac{ 9\pm \sqrt{9^2-4(2)(8)} }{ 2(2) }\) while freckles one: \(\huge x= \frac{ \color{red}{-}9\pm \sqrt{9^2-4(2)(8)} }{ 2(2) } \) that makes waaaaaaaaaaaaay different results. hehehe

OpenStudy (anonymous):

see there you go, they are arguing..

OpenStudy (secret-ninja):

Yep. :/ Oh well, no going back now lol. Thanks for clearing it up though guys :]

OpenStudy (anonymous):

difference is a minus

OpenStudy (anonymous):

simple mistake!

OpenStudy (freckles):

well that isn't what I said...

OpenStudy (freckles):

\[x=\frac{-9 \pm \sqrt{9^2-4(2)(-8)}}{2(2)}\]

OpenStudy (freckles):

she changed the 9's to -9 she said so that wasn't her problem it was she entered in 8 instead of -8

OpenStudy (freckles):

and i didn't know anyone was arguing

OpenStudy (anonymous):

is this finished?

OpenStudy (anonymous):

I mean you have two very proficient members dealing with this problem

OpenStudy (anonymous):

@freckles and @Loser66

OpenStudy (secret-ninja):

?

OpenStudy (secret-ninja):

This question is closed... Its all over. O.o

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