\"\"

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The qudractic equation is \"\".

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Apply subtraction property of equality: If a = b then a \"\" c = b \"\" c.

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\"\"                (Subtract 40s from each side)

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\"\"                              (Apply additive inverse property: \"\")

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The equation compare to quadratic equation, then a = 4, b = - 40 and c = 100.\"\"

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Quadratic formula: \"\".

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\"\" (Substitute x = s, a = 4, b = - 40 and c = 100)

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\"\"    (Evaluate power: \"\")

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\"\"                       (Simplify)

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\"\"

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\"\"

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\"\"

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The solution is \"\".