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Solve the equation 2x^2+2x-1=0 by completing the square

User Rahul Paru
by
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1 Answer

5 votes

Answer:

x = - 1.37 or x = 0.37

Explanation:

2x^2 + 2x -1 = 0 divide the equation by 2 so that the coefficient of x^2 = 1)

(2x^2 + 2x - 1 = 0)/2

= x^2 + x - 1/2 = 0

= x^2 + x = 0.5 ( divide the coefficient of x^2 by 2 and square it )

= (1/2)^2 = 0.5^2 = 0.25

Add 0.25 to both sides of the equation:

x^2 + x + 0.25 = 0.5 + 0.25

(x + 0.5)^2 = 0.75 ( square root both sides)

x + 0.5 = square root +- 0.75

x = - 0.5 +- 0.87

x = - 0.5 + 0.87 = 0.37

x = - 0.5 - 0.87 = -1.37

User Eleanore
by
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