How do you solve using the completing the square method $x^ 2 + 2x + 5 = 0$ ?

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Answer 1 · 2016-09-09T15:10:00

$x=-1-2i$ or $x=-1+2i$

$x^2+2x+5=0$

$hArrx^2+2x+1+4=0$

or $x^2+2xx x xx1+1^2-(-4)=0$

or $(x+1)^2-(2i)^2=0$

Now using identity $a^2-b^2=(a+b)(a-b)$ , this becomes

$(x+1+2i)(x+1-2i)=0$

i.e either $x+1+2i=0$ and $x=-1-2i$

or $x+1-2i=0$ and $x=-1+2i$

How do you solve using the completing the square method x^ 2 + 2x + 5 = 0x^ 2 + 2x + 5 = 0?