9(a-b)²+12(a²-b²)+4(a+b)²
=[3(a-b)]²+2×[3(a-b)]×[2(a+b)]+[2(a+b)]²
=[3(a-b)+2(a+b)]²
=(5a-b)²
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9(a-b)²+12(a²-b²)+4(a+b)²
=[3(a-b)]²+2×[3(a-b)]×[2(a+b)]+[2(a+b)]²
=[3(a-b)+2(a+b)]²
=(5a-b)²
很高兴为您解答,【the 1900】团队为您答题.
请点击下面的【选为满意回答】按钮.