【数学题】先化简再求值:
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【数学题】先化简再求值:
![](http://img.wesiedu.com/upload/6/a9/6a97bab87121269a98784e39d7465f76.jpg)
![](http://img.wesiedu.com/upload/6/a9/6a97bab87121269a98784e39d7465f76.jpg)
![【数学题】先化简再求值:](/uploads/image/z/10717939-19-9.jpg?t=%E3%80%90%E6%95%B0%E5%AD%A6%E9%A2%98%E3%80%91%E5%85%88%E5%8C%96%E7%AE%80%E5%86%8D%E6%B1%82%E5%80%BC%3A)
原式=[(a+b)^2/(a+b)-4ab/(a+b)]/[a(a-b)+b(a+b)-2ab]/(a^2-b^2)
=[(a-b)^2/(a+b)]/[(a-b)^2/(a^2-b^2)]
=(a-b)(a+b)/(a-b)=a+b=4
=[(a-b)^2/(a+b)]/[(a-b)^2/(a^2-b^2)]
=(a-b)(a+b)/(a-b)=a+b=4