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Using properties ofdeterminants, solve the following for x:`|x-2 2x-3 3x-4x-4 2x-9 3x-16 x-8 2x-27 3x-64|=0` |
Answer» Let the given determinant be `Delta`. Then, `Delta = |[x-2,2x-3, 3x-4],[x-4, 2x-9, 3x-16],[x-8,2x-27 ,3x-64]|` `= |[x-2,1, 2],[x-4, -1, -4],[x-8,-11 ,-40]| [C_(1) to (C_(2) -2C_(1)), C_(3) to (C_(3) - 3C_(1))]` `= |[x-2,1, 2],[-2, -2, -6],[-6,-12 ,-42]| [R_(2) to (R_(2) -R_(1)), R_(3) to (R_(3) - R_(1))]` `=(-2) * (-6)* |[x-2,1, 2],[1, 1, 3],[1, 2, 7]|` `=12* |[x-3,1, 2],[0, 1, 3],[-1, 2, 7]| [C_(1) to (C_(1)-C_(2))]` `=12 * [(x-3) (7-6) -1 * (3-2)]` `=12 * (x-4)` `therefore Delta = 0 hArr 12(x-4) = 0 hArr x = 4` Hence, solution set = {4} |
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