Question

can someone help me factor x^2+4x-16?

Answer 1

it's really not factorable

Answer 2

\[x = \frac{-4 \pm \sqrt{16 + 4.16}}{2}\]
\[x = -2 + 2\sqrt{5},-2 - 2\sqrt5\]

Answer 3

unless you use the quadratic formula

Answer 4

ah yeah it is but through myininaya method

Answer 5

do you want to see that

Answer 6

sure

Answer 7

okay then ax^2 + bx + c =0

(b/2 + z)(b/2 - z) = a*c
b^2/4 -z^2 = ac
z^2 = b^2/4 - ac
z = sqrt( b^2 - 4ac)/2

this gives z = 4sqrt5/2 = 2sqrt5

then put b/2+z and b/2 -z inplace of bx

Answer 8

wait a minute i will post a link

Answer 9

http://openstudy.com/users/myininaya#/users/myininaya/updates/4e3a5e000b8bf47d066015a8

Answer 10

x^2+4x-16 = 0 ; -16

x^2 +4x + ___ =16 + ___ ; complete the square

x^2 +4x +4 = 16+4 ; compact it

(x+2)^2 = 20 ; now we can either go further or simply see that sqrt(20) is what we really need so subtract out the 2

-2 + sqrt(20)
-2 - sqrt(20) ; now put into factored form
....................................................
(x +2 - sqrt(20)) (x -2 -sqrt(20))

Answer 11

mighta typoed it .... dbl chk the format :)