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The value of `b` for which the equation `x^2+bx-1=0 and x^2+x+b=0` have one root in common isA. ` - sqrt(2)`B. `-i sqrt(3)`C. `sqrt(2)`D. `sqrt(3)` |
Answer» Correct Answer - 2 ` x^(2) + bx - 1 = 0 ` `x^(2) + x + b = 0 ` Subtracting, we get ` (b - 1) x - 1 - b = 0 ` (1) `rArr x = (b + 1)/(b- 1) ` This value of x satisfies equation (1) `rArr x = ((b + 1) ^(2))/((b- 1) ^(2)) + (b + 1)/(b- 1) + b = 0 ` `rArr b = sqrt(3i), - sqrt(3i), 0` . |
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