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NCERT Class XI Mathematics - Complex Numbers and Quadratic Equations - Solutions

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Question : 29 of 52
Marks: +1, -0
2x2+x+2\sqrt{2}x^2 + x + \sqrt{2} = 0
Solution:  
We have, 2x2+x+2\sqrt{2}x^2 + x + \sqrt{2} = 0
Comparing the given equation with the general form ax2ax^2 + bx + c = 0,
we get a = 2\sqrt{2} , b = 1 , c = 2\sqrt{2}
∴ x = b±b24ac2a\frac{-b\pm\sqrt{b^2-4ac}}{2a} = 1(1)24×2×222\frac{-1\neq\sqrt{(1)^2-4\times\sqrt{2}\times\sqrt{2}}}{2\sqrt{2}}
= 11822\frac{-1\neq\sqrt{1-8}}{2\sqrt{2}} = 1±722\frac{-1\pm\sqrt{-7}}{2\sqrt{2}} = 1±i722\frac{-1\pm i\sqrt{7}}{2\sqrt{2}}
∴ The roots of the given equation are 1+i722\frac{-1+i\sqrt{7}}{2\sqrt{2}} and 1i722\frac{-1-i\sqrt{7}}{2\sqrt{2}}
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