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Solve for x using completing the square:
V^2-6v=-91

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(*)\qquad(a-b)^2=a^2-2ab+b^2\\\\v^2-6v=-91\\\\v^2-2\cdot v\cdot3=-91\ \ \ \ |+3^2\\\\\underbrace{v^2-2\cdot v\cdot3+3^2}_((*))=-91+3^2\\\\(v-3)^2=-82 < 0-NO\ REAL\ SOLUTION\\\\COMPLEX\ SOLUTIONS\\\\v-3=\pm√(-82)\\\\v-3=-i√(82)\ \vee\ v-3=i√(82)\ \ \ \ \ |+3\\\\\boxed{x=3-i√(82)\ \vee\ v=3+i√(82)}

User Alan Pearce
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