先化简,再求值①、(1-x)²(1+x)²/(x²-1)²;其中x=-1/2②、(a+b)²-8(a+b)+16/(a+b)²-16其中a+b=5
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![先化简,再求值①、(1-x)²(1+x)²/(x²-1)²;其中x=-1/2②、(a+b)²-8(a+b)+16/(a+b)²-16其中a+b=5](/uploads/image/z/1746908-44-8.jpg?t=%E5%85%88%E5%8C%96%E7%AE%80%2C%E5%86%8D%E6%B1%82%E5%80%BC%E2%91%A0%E3%80%81%281-x%29%26%23178%3B%281%2Bx%29%26%23178%3B%2F%28x%26%23178%3B-1%29%26%23178%3B%3B%E5%85%B6%E4%B8%ADx%3D-1%2F2%E2%91%A1%E3%80%81%EF%BC%88a%2Bb%EF%BC%89%26%23178%3B-8%EF%BC%88a%2Bb%EF%BC%89%2B16%2F%EF%BC%88a%2Bb%EF%BC%89%26%23178%3B-16%E5%85%B6%E4%B8%ADa%2Bb%3D5)
先化简,再求值①、(1-x)²(1+x)²/(x²-1)²;其中x=-1/2②、(a+b)²-8(a+b)+16/(a+b)²-16其中a+b=5
先化简,再求值①、(1-x)²(1+x)²/(x²-1)²;其中x=-1/2
②、(a+b)²-8(a+b)+16/(a+b)²-16其中a+b=5
先化简,再求值①、(1-x)²(1+x)²/(x²-1)²;其中x=-1/2②、(a+b)²-8(a+b)+16/(a+b)²-16其中a+b=5
① x²-1=(x+1)(x-1),所以(x²-1)²=(1+x)²(1-x)²,所以原式=1
② (a+b)²-8(a+b)+16=(a+b-4)²,(a+b)²-16=(a+b-4)(a+b+4),所以原式=(a+b-4)/(a+b+4),带入a+b=5得1/9