化简,求值:5a²-(3b²+7ab)+(2b²-5a²),其中a=-0.1,b=0.2
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![化简,求值:5a²-(3b²+7ab)+(2b²-5a²),其中a=-0.1,b=0.2](/uploads/image/z/1241601-33-1.jpg?t=%E5%8C%96%E7%AE%80%2C%E6%B1%82%E5%80%BC%EF%BC%9A5a%26%23178%3B-%EF%BC%883b%26%23178%3B%2B7ab%EF%BC%89%2B%EF%BC%882b%26%23178%3B-5a%26%23178%3B%EF%BC%89%2C%E5%85%B6%E4%B8%ADa%3D-0.1%2Cb%3D0.2)
化简,求值:5a²-(3b²+7ab)+(2b²-5a²),其中a=-0.1,b=0.2
化简,求值:5a²-(3b²+7ab)+(2b²-5a²),其中a=-0.1,b=0.2
化简,求值:5a²-(3b²+7ab)+(2b²-5a²),其中a=-0.1,b=0.2
5a²-(3b²+7ab)+(2b²-5a²)
=5a²-3b²-7ab+2b²-5a²
=-b²-7ab
=-(0.2)²-7*(-0.1)*0.2
=-0.04+0.14
=0.1
5a²-(3b²+7ab)+(2b²-5a²)
=5a²-3b²-7ab+2b²-5²
=-b²-7ab
=-(0.2)²-7×(-0.1)×(0.2)
=-0.04+0.14
=0.1
5a²-(3b²+7ab)+(2b²-5a²)
=5a²-3b²-7ab+2b²-5a²
=7ab-b²
当a=-0.1,b=0.2时
7ab-b²
=7×(-0.1)×0.2-0.2²
=-0.14-0.04
=-0.18