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Question
Find the value (s) of x, if `|(1, 4, 20),(1, -2, -5),(1, 2x, 5x^2)|` = 0
Sum
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Solution
`|(1, 4, 20),(1, -2, -5),(1, 2x, 5x^2)|` = 0
∴ 1(– 10x2 + 10x) – 4(5x2 + 5) + 20(2x + 2) = 0
∴ – 10x2 + 10x – 20x2 – 20 + 40x + 40 = 0
∴ – 30x2 + 50x + 20 = 0
∴ 3x2 – 5x – 2 = 0 ...[Dividding throughtout by (– 10)]
∴ 3x2 – 6x + x – 2 = 0
∴ 3x(x – 2) + 1(x – 2) = 0
∴ (x – 2) (3x + 1) = 0
∴ x – 2 = 0 or 3x + 1 = 0
∴ x = 2 or x = `-1/3`
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