Answers

2014-08-06T10:44:55+08:00
X²+4x+1=0
x²+4x+4= -1+4
x+2= 3
√(x+2)² = +- √3
x+2 = +- √3
x= -2 +- √3
x1 = -2 + √3
x2 = -2 - √3
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