Question

What are the solutions of 2x2 + 8x = –26?
The last one I need help understanding. I don't want the answer and I did most of the work I'm stuck at a part tho.

Answer 1

So far i got \[\frac{-8 \pm \sqrt{8^2-4(2)(26)}} {2(2)}\]=\[\frac{-8 \pm \sqrt{64-208}} {4}\]=\[\frac{-8 \pm \sqrt{-144}} {4}\] what I suppose to do from here? Answer, A.\[-2\pm3i\]B.\[-2\pm i\]C.\[2\pm 6i\]D.\[-3\pm 2i\]

Answer 2

Stuck here- \[\sqrt{-144} = \sqrt{-1\times144}\] i think it goes like this \[\sqrt{-144}= \sqrt{-1\times12\times12}=\sqrt{-144}= \sqrt{-1}\times \sqrt{12}\times \sqrt{12}\] I think this is right so far.. :/

Answer 3

@jim_thompson5910 I know I've asked alot of questions today on this but can you help me on my last on please :/

Answer 4

*one

Answer 5

why is this question in the photography section?

Answer 6

its fine and we can work here, just curious

Answer 7

I dont know I feel stupid I clicked on the wrong section and just now saw that :(

Answer 8

that's fine, we can stay here

Answer 9

2x^2 + 8x = –26

2x^2 + 8x + 26 = 0

2(x^2 + 4x + 13) = 0

x^2 + 4x + 13 = 0

Answer 10

oh so i did that all wrong?

Answer 11

You can plug in a = 2, b = 8, c = 26 into the quadratic formula, but I find it easier to simplify as much as possible first

Answer 12

let's go your way, but going either way gets you the same answer

Answer 13

because it all reduces anyway

Answer 14

oh okay

Answer 15

2x^2 + 8x = –26


2x^2 + 8x + 26 = 0


a = 2
b = 8
c = 26


\[\Large x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}\]


\[\Large x = \frac{-(8)\pm\sqrt{(8)^2-4(2)(26)}}{2(2)}\]


\[\Large x = \frac{-8\pm\sqrt{64-208}}{4}\]


\[\Large x = \frac{-8\pm\sqrt{-144}}{4}\]


\[\Large x = \frac{-8+\sqrt{-144}}{4} \ \text{or} \ x = \frac{-8-\sqrt{-144}}{4}\]


\[\Large x = \frac{-8+12i}{4} \ \text{or} \ x = \frac{-8-12i}{4}\]


\[\Large x = -2+3i \ \text{or} \ x = -2-3i\]

Answer 16

If we used a = 1, b = 4, and c = 13, then we would get the same answers, so either path works

Answer 17

oh okay thanks again for all the help :/ I don't understand much of this math that well.

Answer 18

just keep practicing and it will (hopefully) click better

Answer 19

lol I'm sure it will, I'm normal A student in math but doing a grade ahead of my grade level on line is not so easy on your own lol.

Answer 20

dang, that's impressive lol

well keep up the good work

Answer 21

and yes, it's tough on your own without a teacher to help

Answer 22

thanks and yeah it is but I'm doing pretty good I finish my first semester in a totally time of 11weeks today.

Answer 23

that's great, so it's like an accelerated course?

Answer 24

I got held back in 1st grade so I'm a year behind. And so I decided half way through this year that I'd make that year up and graduate next year. I started a little late but I'm making it work. But yeah I'm in 10th and doing 11th grade classes at home online on top of 10th schooling.

Answer 25

well I think a lot of people do since some kids aren't ready for school, but not many would take on two grades to catch up

Answer 26

Yeah. Everyone thinks I'm crazy and I can't do it. But what the heck If it means I finish high school in 3 years and not 4. And I graduate with my age group then so be it. And it will look really good on collage applications lol.

Answer 27

yeah for sure, it will show that you're a very hard worker, which is what I would look for most in a potential employee

Answer 28

lol and that's fuel to show them wrong and that you can do it

Answer 29

Yeah well nice chatting and thanks for helping me get to the answer and not just giving it to me. But I got to go finish these math essay questions I have to do now. then go take my semester 1 finals exam. And I can't not tell you how thankful I am! :D

Answer 30

glad to be of help, good luck with the rest of it and your classes (and 2 grade levels)

Answer 31

Thanks! :)

Answer 32

o-o