Question number 2, @satellite73
can't wait
\[9x^2-16x+60=0\]\[ax^2+bx+c=0\] the distriminant is \[b^2-4ac\]which is our cases is \[(-16)^2-4\times 9\times 60\]
if my arithmetic is right, this is \[(-16)^2-4\times 9\times 60=-1904\] does that look right?
From what I know which is not much lol it looks pretty right to me (:
k good ( i used a calculator) there are 3 possibilities for the discriminant a) is it positive meaning there will be two real solutions to the equation b) it is zero, which means there will be one real solution c) it is negative (our case) meaning there will be NO real solutions that is the answer h ere
so when its negative there are no real solutions?
right
how about \[4x^2+8x-5=0\] my suggestion is to factor it if you can
Okay yeah i can do that but i have to explain as to why i chose to factor it could you tell me why you suggest it? To me it seems like the easiest method idk
you want a hint? t is \[(2 x-1) (2 x+5) = 0\] factor because what you said, it is the easiest method if you can do it
and also in this case you don't have too many choices because \(-5=-1\times 5\) or \(5\times (-1)\) so it is not hard to come up with \[(2 x-1) (2 x+5) = 0\]
Okay thank you (:
you can solve that, right?
\[2x-1=0\\ 2x=1\\x=\frac{1}{2}\] for the first one
yep i can (: and okay thanks
good
wait this is going to come out dumb i suppose but are we still on part b or did we go to C? sorry little tiny bit confused
we did part B solved \[4x^2+8x-5=0\]
\[(2 x-1) (2 x+5) = 0\] \[2x-1=0\\ 2x=1\\ x=\frac{1}{2}\] or \[2x+5=0\\ 2x=-5\\ x=-\frac{5}{2}\] are the two solutions
okay yes got that, thanks for clearing up my confusion
k now how about the last one i guess you can't factor it
yeah and factoring is like the easiest method i know ):
\[2x^2-12x+5=0\] we can complete the square
subtract 5 from both sides to get \[2x^2-12x=-5\] then divide by 2 and ge t \[x^2-6x=\frac{5}{2}\] are the first two steps write them down, let me know when you want to continue
okay done writing that down (:
ok now we take half of 6, which is 3 and square it to get 9, and write \[(x-3)^2=-\frac{5}{2}+9\] or \[(x-3)^2=\frac{13}{2}\]
maybe it would have been easier to use the quadratic formula, i don't know, but we are almost done
okay i wrote both of them down
you get \[x-3=\pm\frac{\sqrt{13}}{\sqrt2}\] so \[x=3\pm\frac{\sqrt{13}}{\sqrt2}\]
next job i get will be doing math at mystic falls
okay thankss (: and lol well that would be a little complicated cause mystic falls is actually a fictional town from the vampire diaires xD i actually go to FLVS
yeah i know i googled it
well, i didn't know about FLVS and don't even know what that is
florida virtual school (: its home school but on a computer lol
wow must be hard to learn math that way at least you can get help here do you have to turn this in? like written out on paper? or through a computer
through the computer, we could mail our work to the teachers but it would take a while for it to get there so our teachers dont want us to.
ok i assume you want to be done right? because we could redo the last one using the quadratic formula if you think it would look better to the teacher
Oh no its fine, plus i kinda need to finish up cause its 11pm and i have to go to bed soon lol so can we go onto my last question?
you got one more?
cause that was the last one, the one where we got \[x=3\pm\frac{\sqrt{13}}{\sqrt2}\]
oh yeah i know lol but i have one last question i need to work on if you cant help me now thats fine we can finish up tomorrow (:
go ahead an post, maybe we can do it quickly
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