SOLUTION: Hello,Well im stuck on this Quadratic formula.I really need your help, because I tried to do it my self but im not doing it right I guess because the answer im getting is not the a

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: Hello,Well im stuck on this Quadratic formula.I really need your help, because I tried to do it my self but im not doing it right I guess because the answer im getting is not the a      Log On


   

Question 238836: Hello,Well im stuck on this Quadratic formula.I really need your help, because I tried to do it my self but im not doing it right I guess because the answer im getting is not the answers provided. Can you help me please?
Problem:x^2-8x+30=0
My work:a=1, b=-8, c=30
x=[8+-(-8^(2)-4(1)(30))^(1/2)]/2(1)
=[8+-(64-120)^(1/2)]/2
=[8+-(-56)^(1/2)]/2
=[8+-2i(14)^(1/2)]/2
=4+-i(14)^(1/2)
My options:
A.) -4+4i,-4-4i
B.)4+4i,4-4i
C.)4+8i,4-8i
D.)-4+8i,-4-8i
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Problem:x^2 -8x + 30 = 0
My work:a=1, b=-8, c=30
:
x+=+%28-%28-8%29+%2B-+sqrt%28-8%5E2-4%2A1%2A30+%29%29%2F%282%2A1%29+
:
x+=+%288+%2B-+sqrt%2864+-+120+%29%29%2F2+
:
x+=+%288+%2B-+sqrt%28-56+%29%29%2F2+
:
x+=+%288+%2B-+sqrt%28-4%2A14%29%29%2F2+
:
x+=+%288+%2B-+2i%2Asqrt%2814%29%29%2F2+
:
x+=+4+%2B-+i%2Asqrt%2814%29+; I got the same thing you got
:
Hey!
We can prove it, find the equation using our solution:
x+=+4+%2B-+i%2Asqrt%2814%29+
:
x+-+4+=+i%2Asqrt%2814%29+
:
Square both sides
(x-4)^2 = i^2(14)
Which is
x^2 - 8x + 16 = -1(14)
x^2 - 8x + 16 = -14
x^2 - 8x + 16 + 14 = 0
x^2 - 8x + 30 = 0; does that look familiar?