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If f(x) = x2 – x then f(x – 1) – f(x + 1) is …(1) 4x(2) 4x + 2(3) 2 – 4x(4) 4x – 2 |
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Answer» (3) 2 – 4x f(x – 1) = (x – 1)2 – (x – 1) = x2 – 2x + 1 – x + 1 = x2 – 3x + 2 f(x + 1) = (x + 1)2 – (x + 1) = x2 + 2x + 1 – x – 1 = x2 + x f(x – 1) – f(x + 1) = x2 – 3x + 2 – (x2 + x) = x2 – 3x + 2 – x2 – x = -4x + 2 = 2 – 4x |
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