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问题: 一道二元一次的计算题

(3-√2)^2(3+√2)+(3+√2)^2(3-√2)
怎么做(过程)

解答:

(3-√2)^2(3+√2)+(3+√2)^2(3-√2) =
(3-√2)[(3-√2)(3+√2)]+(3+√2)[(3+√2)(3-√2)] =
(3-√2)(9-2)+(3+√2)(9-2) =
(3-√2)*7+(3+√2)*7 =
[(3-√2)+(3+√2)]*7 =
6*7=42