a+bi form

[moronatmath]

Whats up? I need some help with this problem please.
Find all solutions of the equation x^2 + 2 x + 5 = 0 and express them in the form a + b i:

Here is my attempt. First use the quadratic formula
a=1 b=2 c=5

x= -2 plus or minus sqrt(2^2-4(1)(5))/2(1)

simplified i got

x= -2 plus or minus sqrt -16/2

ok so for the a+bi form I got
-2+(sqrt(16)/2)i, 2-(sqrt(16)/2)i

Can someone please tell me were I went wrong? I appreciate it!

 

[tkhunny]

You stopped too soon.

\(\displaystyle \L\sqrt{16}=4\)

 

[Mrspi]

Whats up? I need some help with this problem please.
Find all solutions of the equation x^2 + 2 x + 5 = 0 and express them in the form a + b i:

Here is my attempt. First use the quadratic formula
a=1 b=2 c=5

x= -2 plus or minus sqrt(2^2-4(1)(5))/2(1)

simplified i got

x= -2 plus or minus sqrt -16/2

ok so for the a+bi form I got
-2+(sqrt(16)/2)i, 2-(sqrt(16)/2)i

Can someone please tell me were I went wrong? I appreciate it!

You have

(-2 ±√-16)/2

√-16 is 4i

(-2 ± 4i)/2

(-2/2) ± (4i/2)

-1 ± 2i

Your two solutions should be
-1 + 2i
and
-1 - 2i