x²-4x+4=2+4
(x-2)²=6
x-2=±√6
x=2-√6,x=2+√6
x²+5x=-5
x²+5x+25/4=-5+25/4
(x+5/2)²=5/4
x+5/2=±√5/2
x=(-5-√5)/2,x=(-5+√5)/2
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