搜搜考试网计算题和先化简,在求值,
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计算题和先化简,在求值,
计算题 丨1-√2丨+√8-sin30°-6/√2+(π-3.14)^0
先化简,在求值(x-1-8/x+1)÷x^2+2x-3/1-x^2,其中x=-2
计算题 丨1-√2丨+√8-sin30°-6/√2+(π-3.14)^0
先化简,在求值(x-1-8/x+1)÷x^2+2x-3/1-x^2,其中x=-2
解
原式
=√2-1+2√2-1/2-3√2+1
=(√2+2√2-3√2)+(-1-1/2+1)
=-1/2
[(x-1)-8/(x+1)]÷[(x²+2x-3)/(1-x²)]
=[(x²-1)/(x+1)-8/(x+1)]×(1-x)(1+x)/(x+3)(x-1)
=(x²-1-8)/(x+1)×[-(x+1)/(x+3)]
=-(x-3)(x+3)/(x+1)×(x+1)/(x+3)
=-(x-3)
=-(2-3)
=1
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原式
=√2-1+2√2-1/2-3√2+1
=(√2+2√2-3√2)+(-1-1/2+1)
=-1/2
[(x-1)-8/(x+1)]÷[(x²+2x-3)/(1-x²)]
=[(x²-1)/(x+1)-8/(x+1)]×(1-x)(1+x)/(x+3)(x-1)
=(x²-1-8)/(x+1)×[-(x+1)/(x+3)]
=-(x-3)(x+3)/(x+1)×(x+1)/(x+3)
=-(x-3)
=-(2-3)
=1
再问： http://zhidao.baidu.com/question/262663421745506765.html�ش�һ������� лл
再答： ���Ѿ��ش��ˣ��뼰ʱ�����������