初中数学七年级上册（581题）

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已知\(|x + 1| = 4\)，\({(y + 2)^2} = 4\)，求\(x + y\)的值．

知识点：第一章 有理数

参考答案：解：\(\because |x + 1| = 4\)，\({(y + 2)^2} = 4\)，\(\therefore x + 1 = 4\)，或\(x + 1 = - 4\)，\(y + 2 = 2\)或\(y + 2 = - 2\)，解得\(x = 3\)或\(x = - 5\)，\(y = 0\)或\(y = - 4\)，\(\therefore x = 3\)，\(y = 0\)时，\(x + y = 3 + 0 = 3\)；\(x = 3\)，\(y = - 4\)时，\(x + y = 3 - 4 = - 1\)；\(x = - 5\)，\(y = 0\)时，\(x + y = - 5 + 0 = - 5\)；\(x = - 5\)，\(y = - 4\)时，\(x + y = - 5 - 4 = - 9\)．