1.

2x^2 - 3x - 1 = 0 by completing the square

Answer»

Given 2x2 - 3x - 1 = 0

x2 - 3/2 x - 1/2 = 0

x2 - 3/2 x = 1/2

x2 - 3/2 x + (3/4)2 = 1/2 + (3/4)2

\({{(x-3)}\over2}^2\) = 1/2 + 9/16

\({{(x-3)}\over2}^2\) = (8+9)/16

x - 3/2 = ±\(\sqrt{17}\)/4

x = +\(\sqrt{17}\)/4 + 3/2

⇒ \(\frac{(\sqrt{17}+ 6)}4\)

x = - \(\sqrt{17}\)/4 + 3/2

⇒ \(\frac{(-\sqrt{17}+ 6)}4\)



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