Question

I cant get his problem, I'm working with Solving Quadratic Equations: the Principle of Square Roots

2x^(2)-8x=14

I know that i'm supposed to divide the entire question by 2, then take half of the coefficient of x, but its not coming out. What am i doing wrong?

Answer 1

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Answer 2

\[2x ^{2}-8x=14\]

Answer 3

taking half throughout the equation u get,
x^2-4x-7=0
then,
x^2 -4x+4-4-7=0
=> (x-2)^2=11
therefore we get,
x=2+-sqrt(11);

Answer 4

yan po ung sgot ?

Answer 5

err...which language is that ?

Answer 6

is that the answer ?

Answer 7

yes that is the answer, let me look at what you did

Answer 8

if u hav doubt post it :)

Answer 9

do u all have a facebook ?

Answer 10

\[2x ^{2}-8x=14\]
then i moved the 14 over
\[2x ^{2}-8x-14=0\]
then i divided the entire equation by 2
\[x ^{2}-4x-7=0\]
then i moved the 7 back over
\[x ^{2}-4x=7\]
so if i take the half of the coeffient of x, i end up with
\[x2-4x+4=7\]

i dont understand how you got \[\sqrt{11}\]

Answer 11

this x^2 -4x+4-4-7=0 i dont understand

Answer 12

use the quadratic formula

Answer 13

ok let me try that

Answer 14

in deriving the last equation , u forgot that wen u add 4 u need to subtract it too! get it?

Answer 15

ok, i got it using the quadratic formula

Answer 16

ur saying when i added for, i then need to subtract if from 7?

Answer 17

four

Answer 18

u hv to carry out same operation on both sides to maintain equality

Answer 19

ok look at the last but one equation.
u hav x^2-4x=7
and then u hav got
x^2-4x+4=7 , which ur telling ,are the same 2 equations.

wat i'm telling is, u should hav done x^2-4x+4=7+4

Answer 20

ohh yes thats right

Answer 21

but i still have x2-4x+4=11

Answer 22

the x2-4x+4 cannot be factored

Answer 23

oh pellet, i got it yes it can

Answer 24

so it shud b x^2 - 4x +4 = 11
the left hand side become (x -2)^2
so (x-2)^2 = 11
so x+2 = +/- root11
x = -2 +/-root11

Answer 25

\[(x-2)^{2}=\sqrt{11}\]

Answer 26

yes, thank you all!
for some reason i just could not see this

Answer 27

no plus-minus root11

Answer 28

yes the final is \[x=2+-\sqrt{11}\]

Answer 29

\[(x-2) = \pm \sqrt{11}\]

Answer 30

yes final is what u wrote

Answer 31

thanks you! you all are great!

Answer 32

i just could not get what i was missing

Answer 33

its so silly when i look at it now

Answer 34

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Answer 35

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Answer 36

if i find that button i will..lol

Answer 37

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Answer 38

got it

Answer 39

tku very much !!!!