先化简,后求值 (a+2b)²-(a-b)(a-4b),其中a=1/3,b=2我重新打一遍(a+2b)的平方-(a-b)(a-4b),其中a=1/3,b=2
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![先化简,后求值 (a+2b)²-(a-b)(a-4b),其中a=1/3,b=2我重新打一遍(a+2b)的平方-(a-b)(a-4b),其中a=1/3,b=2](/uploads/image/z/2681802-18-2.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%90%8E%E6%B1%82%E5%80%BC+%28a%2B2b%29%26sup2%3B-%28a-b%29%28a-4b%29%2C%E5%85%B6%E4%B8%ADa%3D1%2F3%2Cb%3D2%E6%88%91%E9%87%8D%E6%96%B0%E6%89%93%E4%B8%80%E9%81%8D%28a%2B2b%29%E7%9A%84%E5%B9%B3%E6%96%B9-%28a-b%29%28a-4b%29%EF%BC%8C%E5%85%B6%E4%B8%ADa%3D1%2F3%2Cb%3D2)
先化简,后求值 (a+2b)²-(a-b)(a-4b),其中a=1/3,b=2我重新打一遍(a+2b)的平方-(a-b)(a-4b),其中a=1/3,b=2
先化简,后求值 (a+2b)²-(a-b)(a-4b),其中a=1/3,b=2
我重新打一遍
(a+2b)的平方-(a-b)(a-4b),其中a=1/3,b=2
先化简,后求值 (a+2b)²-(a-b)(a-4b),其中a=1/3,b=2我重新打一遍(a+2b)的平方-(a-b)(a-4b),其中a=1/3,b=2
(a+2b)^2-(a-b)(a-4b)
=a^2+4b^2+4ab-a^2+5ab-4b^2
=9ab
=9*1/3*2
=6