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In equation `x^4-2x^3+4x^2+6x-21=0`if two its roots are equal inmagnitude but opposite e in find the roots. |
Answer» Given that `alpha + beta = 0 but alpha + beta + gamma + delta = 2`. Hence , `gamma + delta = 2` Let `alpha beta = p and gamma delta = q.` Therefore, given equation is equivelent to `(x^(2) + P)(x^(2) -2x + q) = 0`. Comparing the coefficients, we get `p + q = 4, -2p = 6 , pq = -21` .Therefore, p = -3, q = 7 and they satisfy pq = -21. Hence, `(x^(2) - 3)(x^(2) - 2x + 7) = 0` Therefore, the roots are `pm i sqrt(6)(where i = sqrt(-1))` |
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