先化简再求值:-2(mn-3m²)-[m²-5(mn-m²)+2mn],其中m=1 n=-2
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![先化简再求值:-2(mn-3m²)-[m²-5(mn-m²)+2mn],其中m=1 n=-2](/uploads/image/z/594319-31-9.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%E5%86%8D%E6%B1%82%E5%80%BC%EF%BC%9A-2%28mn-3m%26%23178%3B%29-%5Bm%26%23178%3B-5%28mn-m%26%23178%3B%29%2B2mn%5D%2C%E5%85%B6%E4%B8%ADm%3D1+n%3D-2)
先化简再求值:-2(mn-3m²)-[m²-5(mn-m²)+2mn],其中m=1 n=-2
先化简再求值:-2(mn-3m²)-[m²-5(mn-m²)+2mn],其中m=1 n=-2
先化简再求值:-2(mn-3m²)-[m²-5(mn-m²)+2mn],其中m=1 n=-2
-2(mn-3m²)-[m²-5(mn-m²)+2mn]
=-2mn+6m²-m²+5mn-5m²-2mn
=mn
=1x-2
=-2