请快解出来,谢谢1-3题要先化简再求值!先化简在求值,1.{(2m+n)²+(2m+n)(2m-n)}/2m 其中m=3,n=1/22.{(x-y)²-(x+y)²+(x+y)×(x-y)+5y²}/(x-2y) 其中x=3/2,y=1/23{(a+b)²-4(ab+1/4)}/(a
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![请快解出来,谢谢1-3题要先化简再求值!先化简在求值,1.{(2m+n)²+(2m+n)(2m-n)}/2m 其中m=3,n=1/22.{(x-y)²-(x+y)²+(x+y)×(x-y)+5y²}/(x-2y) 其中x=3/2,y=1/23{(a+b)²-4(ab+1/4)}/(a](/uploads/image/z/14309933-5-3.jpg?t=%E8%AF%B7%E5%BF%AB%E8%A7%A3%E5%87%BA%E6%9D%A5%2C%E8%B0%A2%E8%B0%A21-3%E9%A2%98%E8%A6%81%E5%85%88%E5%8C%96%E7%AE%80%E5%86%8D%E6%B1%82%E5%80%BC%21%E5%85%88%E5%8C%96%E7%AE%80%E5%9C%A8%E6%B1%82%E5%80%BC%2C1.%7B%EF%BC%882m%2Bn%29%26%23178%3B%2B%282m%2Bn%29%282m-n%29%7D%2F2m+%E5%85%B6%E4%B8%ADm%3D3%2Cn%3D1%2F22.%7B%EF%BC%88x-y%EF%BC%89%26%23178%3B-%EF%BC%88x%2By%EF%BC%89%26%23178%3B%2B%EF%BC%88x%2By%EF%BC%89%C3%97%EF%BC%88x-y%EF%BC%89%2B5y%26%23178%3B%7D%2F%EF%BC%88x-2y%EF%BC%89+%E5%85%B6%E4%B8%ADx%3D3%2F2%2Cy%3D1%2F23%7B%EF%BC%88a%2Bb%EF%BC%89%26%23178%3B-4%EF%BC%88ab%2B1%2F4%EF%BC%89%7D%2F%EF%BC%88a)
请快解出来,谢谢1-3题要先化简再求值!先化简在求值,1.{(2m+n)²+(2m+n)(2m-n)}/2m 其中m=3,n=1/22.{(x-y)²-(x+y)²+(x+y)×(x-y)+5y²}/(x-2y) 其中x=3/2,y=1/23{(a+b)²-4(ab+1/4)}/(a
请快解出来,谢谢1-3题要先化简再求值!
先化简在求值,
1.{(2m+n)²+(2m+n)(2m-n)}/2m 其中m=3,n=1/2
2.{(x-y)²-(x+y)²+(x+y)×(x-y)+5y²}/(x-2y) 其中x=3/2,y=1/2
3{(a+b)²-4(ab+1/4)}/(a-b+1) 其中a=2,b=1/2
4{a(a+2b)+b²} ×{a²-b(2a-b)} /(a²-b²)² (此题化简,
5.已知a.b.c为有理数,而且多项式x³+ax²+bx+c能够被x²+3x-4整除
问1.求4a-2b-c的值 2.若a,b,c为整数时,且c≥a>1,请尝试确定a,b,c的大小
请快解出来,谢谢1-3题要先化简再求值!先化简在求值,1.{(2m+n)²+(2m+n)(2m-n)}/2m 其中m=3,n=1/22.{(x-y)²-(x+y)²+(x+y)×(x-y)+5y²}/(x-2y) 其中x=3/2,y=1/23{(a+b)²-4(ab+1/4)}/(a
1.{(2m+n)²+(2m+n)(2m-n)}/2m 其中m=3,n=1/2
=(2m+n)(2m+n+2m-n)/2m
=2m(2m+n)
=2*3(2*3+1/2)
=39
2.{(x-y)²-(x+y)²+(x+y)×(x-y)+5y²}/(x-2y) 其中x=3/2,y=1/2
=(x²-2xy+y²-x²-2xy-y²+x²-y²+5y²)/(x-2y)
=(x²-4xy+3y²)/(x-2y)
=(x-y)(x-3y)/(x-2y)
=(3/2-1/2)(3/2-3/2)/(3/2-1)
=0
3{(a+b)²-4(ab+1/4)}/(a-b+1) 其中a=2,b=1/2
=(a²+2ab+b²-4ab-1)/(a-b+1)
=[(a-b)²-1]/(a-b+1)
=(a-b-1)(a-b+1)/(a-b+1)
=a-b-1
=2-1/2-1
=1/2
4{a(a+2b)+b²} ×{a²-b(2a-b)} /(a²-b²)² (此题化简,
=(a²+2ab+b²)(a²-2ab+b²)/[(a-b)(a+b)]²
=(a+b)²(a-b)²/[(a+b)²(a-b)²]
=1
5.已知a.b.c为有理数,而且多项式x³+ax²+bx+c能够被x²+3x-4整除
问1.求4a-2b-c的值
x³+ax²+bx+c=(x+n)(x²+3x-4)=x³+(n+3)x²+(3n-4)x-4n
∴a=n+3 b=3n-4 c=-4n
4a-2b-c=4n+12-6n+8-4n=20-6n
2.若a,b,c为整数时,且c≥a>1,请尝试确定a,b,c的大小
∵a=n+3 b=3n-4 c=-4n 且c≥a>1
令n=-1
∴a= 2 b=-7 c=4
∴ c>a>b