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3（a+1）(a+1)-5(1+a)(a-1)+2(a-1)(a-1),其中a=-1/2
题目详情
3（a+1）(a+1)-5(1+a)(a-1)+2(a-1)(a-1),其中a=-1/2
▼优质解答
答案和解析
3(a+1)²-5(1+a)(a-1)+2(a-1)²
=3(a+1)²-5(a+1)(a-1)+2(a-1)²
=[(a+1)-(a-1)][3(a+1)-2(a-1)]
=2(a+5)
=2×(-1/2+5)
=2×(9/2)
=9
提示：先将a+1,a-1分别看做整体,因式分解.
=3(a+1)²-5(a+1)(a-1)+2(a-1)²
=[(a+1)-(a-1)][3(a+1)-2(a-1)]
=2(a+5)
=2×(-1/2+5)
=2×(9/2)
=9
提示：先将a+1,a-1分别看做整体,因式分解.
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