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Solve : 4x3 – 24x2 + 23x +18 = 0, given that the roots of this equation are in arithmetic progression. |
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Answer» Let a – d, a, a + d are the roots of the given equation. Now, sum of the roots a – d + a + a + d = 24/4 3a = 6 a = 2 Product of the roots (a – d)a(a + d)= −18/4 a(a2 – d2) = – 9/2 = 2(4 – d2) = – 9/2 4(4 – d2) = – 9 16 – 4d2 = – 9 4d2 = 25 d = ±5/2 ∴ roots are -1/2, 2 and 9/2 |
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