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X^2-2x=5 solve by completing the square

1 Answer

5 votes

Answer:

x = ± sqrt(6) + 1

Explanation:


x^2 - 2x = 5

First, add half of -2 squared to both sides:


x^2 - 2x + (-(2)/(2))^2 = 5 + (-1)^2


x^2 - 2x + 1 = 5 + 1


x^2 - 2x + 1 = 6

Then, factor the perfect square trinomial on the left:


(x - 1)^2 = 6

Finally, square root both sides:


√((x - 1)^2) = √(6)


x - 1 = √(6) or
x - 1 = -√(6)

x = ± sqrt(6) + 1

User Croixhaug
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