①先化简,在求值.8m²-2(3m+4m²-10-8,其中m=-1.②求当a=-½,b=1时,代数式2a²b-[2ab²-2(a²b+2ab²)]的值.
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![①先化简,在求值.8m²-2(3m+4m²-10-8,其中m=-1.②求当a=-½,b=1时,代数式2a²b-[2ab²-2(a²b+2ab²)]的值.](/uploads/image/z/8219158-70-8.jpg?t=%E2%91%A0%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%9C%A8%E6%B1%82%E5%80%BC.8m%26%23178%3B-2%EF%BC%883m%2B4m%26%23178%3B-10-8%2C%E5%85%B6%E4%B8%ADm%3D-1.%E2%91%A1%E6%B1%82%E5%BD%93a%3D-%26%23189%3B%2Cb%3D1%E6%97%B6%2C%E4%BB%A3%E6%95%B0%E5%BC%8F2a%26%23178%3Bb-%5B2ab%26%23178%3B-2%EF%BC%88a%26%23178%3Bb%2B2ab%26%23178%3B%EF%BC%89%5D%E7%9A%84%E5%80%BC.)
①先化简,在求值.8m²-2(3m+4m²-10-8,其中m=-1.②求当a=-½,b=1时,代数式2a²b-[2ab²-2(a²b+2ab²)]的值.
①先化简,在求值.8m²-2(3m+4m²-10-8,其中m=-1.
②求当a=-½,b=1时,代数式2a²b-[2ab²-2(a²b+2ab²)]的值.
①先化简,在求值.8m²-2(3m+4m²-10-8,其中m=-1.②求当a=-½,b=1时,代数式2a²b-[2ab²-2(a²b+2ab²)]的值.
1、少了个括号,应该是8m^2-2(3m+4m^2-10)-8吧?
原式=8m^2 -6m-8m^2 +20-8
=-6m+12
=6+12
=18
2、原式=2ba^2 -[-2ab^2 -2ba^2]
=2ab^2 +4ba^2
=2*(-1/2)+4*(1/4)
=0