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alexghe92
solve: x^2-2x+4=0
quadratic formula In: \[ax^2 + bx + c = 0\] \[x _{1,2} = (-b \pm \sqrt{b^2-4ac}) / 2a\] plug it in \[x _{1,2} = (-(-2) \pm \sqrt{(-2)^2-4(1)(4)}) / 2(1)\] which equals 2 plus or minus sqrt(4-16) = 2+2(i)sqrt(3) or 2-2(i)sqrt(3) \[i = \sqrt{-1}\]