Two students, Tom and Mary, solved the equation at the same time. Tom thought that the solutions of the equation were 1 and – 9, but he misread the corresponding number of c in the calculation. Mary thought that the solutions of the equation were 1 and 7, but Mary mistook the corresponding number of b in the calculation. What are correct solutions of this equation?
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A1,7
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B1,9
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C7,9
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D-1,-7
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E-1,-9
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正确答案: D