Question

How did you get -6? x^2+4x-12=0

Answer 1

do you know how to factor this ?

Answer 2

if you need more info on factoring, this might help (when you have time)
https://www.khanacademy.org/math/algebra/multiplying-factoring-expression/factoring-quadratic-expressions/v/factoring-quadratic-expressions

Answer 3

but to answer your question
x^2+4x-12
can be factored into
(x+6)(x-2)
if you multiply that out you will get x^2 +6x -2x -12 which simplifies to
x^2 +4x -12 (i.e. what we started with)
\[ x^2+4x-12=0 \\ \text{ becomes } \\(x+6)(x-2) = 0 \]

when you multiply two "things" and get zero, that must mean one or the other (or both) is zero

so either
x+6 =0
or
x-2 = 0

the first equation x+6=0 gives us
x+6 -6 = 0 -6 or
x = -6

the second equation gives us x=2

so there are two different x values that make your equation true.

Answer 4

yes i have for i have.

x^2+4x+4=12 +4

then i ended up with (x+2)^2= 16

which gave me x +/- 4

x+2=4
= 2

x-2= -4
= -2
but i type the equation into my calculator (y=), i'm supposed to end up with x=2 and x= -6

Answer 5

(x+2)^2= 16

take the square root of both sides
\[ x+2 = \pm 4 \]
we should write that as two separate equations:
x+2 = +4
and
x+2 = -4
(notice this is different from what you wrote: x-2 = -4. )

Answer 6

thank you so much. (:

Answer 7

yw