已知x^m=3,x^=2,求x^2m-3n的值.3/8*（x-2y)^9除2/3（2y-x)^4,计算结果写成（x-2y

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已知x^m=3,x^=2,求x^2m-3n的值.3/8*（x-2y)^9除2/3（2y-x)^4,计算结果写成（x-2y)的幂的形式先化简,在求值｛（x-y)^2+(x+y)(x-y)除2x,其中x=3,y=-1,5.已知2a-b=8,求｛（a^2+b^2)-(a-b)^2+2b(a-b)｝除4b的值

x^2m-3n=x^2m/x^3n=x^m^2/x^n^3=9/8
是除以吧.3/8*（x-2y)^9除2/3（2y-x)^4=3/8*（x-2y)^9除2/3（x-2y)^4=9/16*（x-2y)^5
｛（x-y)^2+(x+y)(x-y)除2x=(2*x^2-2xy)除2x=2x(x-y)除2x=x-y=4.5
｛（a^2+b^2)-(a-b)^2+2b(a-b)｝除4b=(4ab-2b^2)除4b=2b(2a-b)除4b=16b除4b=4
好辛苦的,一定要把分给我哦

已知x^m=3,x^=2,求x^2m-3n的值.3/8*（x-2y)^9除2/3（2y-x)^4,计算结果写成（x-2y 已知方程组{4x+y=3m 2x-2y=9m,求x+y+m/3x-2y的值. 已知x.y满足2x-y=3m,x+2y=4m+5,且x+y=9,求m的值整体求值 1.已知:x-2y=3,求[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]除4x 的值已知(x+y+3)(x-my+n)=x平方-xy-2y平方+5x-4y=6,求m,n的值已知关于X,Y的方程组X+Y=5m,X-Y=9m的满足2X+3Y=6,求m的值已知X、Y满足2X-7Y=3M,X+2Y=4m+5,且X+Y=0,求M的值已知x.y满足2x-y=3m,x+2y=4m+5,且x+y=0,求m的值已知x,y满足2x-y=3m,x+2y=4m+5,且x+y=0,求m的值已知x,y满足2x-7y=3m,x+2y=4m+5,且x+y=o,求m的值已知M=（y|y=x的平方-4X+3,X属于R）N=（y|y=-X的平方+2X+8,X属于R）求M交与N 计算：(y-x)^3(x-y)^m-(x-y)^m+2(y-x)