January 19th, 2017, 02:35 PM  #1 
Senior Member Joined: Feb 2016 From: seattle Posts: 377 Thanks: 10  quadratic formula...But this time with a negative
says some thing about an I ?

January 19th, 2017, 02:40 PM  #2 
Senior Member Joined: Feb 2016 From: seattle Posts: 377 Thanks: 10 
At this point now

January 19th, 2017, 02:48 PM  #3 
Senior Member Joined: Feb 2016 From: seattle Posts: 377 Thanks: 10 
now here and stuck.

January 19th, 2017, 03:17 PM  #4 
Senior Member Joined: Sep 2015 From: USA Posts: 2,496 Thanks: 1371  I don't know how they expect you to do these if you haven't been taught at least rudimentary complex numbers. There exists a number generally called $i$ which is defined such that $i^2 = 1$ so when you see something like $\sqrt{444}$ this is $\sqrt{i^2 444} = i\sqrt{444}$ $i$ is the unit imaginary number, similar to the way $1$ is the unit real number. The complex numbers are all numbers of the form $a + i b, ~a, b \in \mathbb{R}$ 
January 19th, 2017, 03:55 PM  #5 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 14,597 Thanks: 1038 
Ya gotta be more careful, Joe me boy! Given equation is: (a  8 )(a  2) = 1 Simplifies to: a^2  10a + 16 = 1 Continue... 
January 19th, 2017, 04:30 PM  #6 
Math Team Joined: Jul 2011 From: Texas Posts: 2,978 Thanks: 1573  $a^210a+17 = 0$ quadratic formula $a=1$, not $8$ $b=10$ and $c=17$ $b^24ac = 100  4(1)(17) = 32$ now finish it ... you've been your own worst enemy by not paying attention to detail. 
January 19th, 2017, 09:36 PM  #7  
Senior Member Joined: Feb 2016 From: seattle Posts: 377 Thanks: 10  Quote:
 
January 19th, 2017, 09:56 PM  #8  
Senior Member Joined: Sep 2015 From: USA Posts: 2,496 Thanks: 1371  Quote:
So it makes more sense that you hadn't seen complex numbers yet. You'd have seen them eventually.  
January 25th, 2017, 10:14 AM  #9 
Senior Member Joined: Feb 2016 From: seattle Posts: 377 Thanks: 10  Thanks Yes I still make mistakes but the video that was given to me by My math class said I would be dealing with a negative so When i got what was above I thought I had gotten the situation I was meant to get.

January 25th, 2017, 04:04 PM  #10 
Math Team Joined: Jan 2015 From: Alabama Posts: 3,264 Thanks: 902 
Your basic problem, GIJoefan1986, is that you multiplied (x 8 )(x 2) and got rather than ! Where in the world did that come from?


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formulabut, negative, negitive, quadratic, time 
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