x-y=6,xy=-8
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题目写错应该是求(6xy+7y)+[8x-(5xy-y+6x)](6xy+7y)+[8x-(5xy-y+6x)]=6xy+7y+8x-5xy+y-6x=xy+2x+8y=xy+2(x+4y)=5+2×
x-xy=8(1)xy-y=-9(2)则有(1)-(2):X-XY-XY+Y=X+Y-2XY=8-(-9)=17
(5X-4Y-3XY)-(8X-Y+2XY)=-(3X+3Y)-5XY=-3*6+4*5=2
解题思路:本题是求整式的值,注意一定要先化简,再求值。化简就是先去括号,在合并同类项。解题过程:解:(6xy+7y)+[8x-(5xy-y+6x)]=(6xy+7y)+[8x-5xy+y-6x]=6x
原式=6xy+7y+8x-5xy+y-6x=xy+2x+8y=xy+2(x+4y)=···再问:还有些题哈……
原式=6xy+7y+8x-5xy+y-6x=xy+8y+2x=xy+2(x+4y)=5+2×(-1)=3
6xy+7y)+【8x-(5xy-y+6x)】=xy+8y+2x=xy+2(4y+x)=5-2=3
原式=6xy+7y+8x-5xy+y-6x=xy+2(4y+x)=5-2=3
(6xy+7y)+[8x-(5xy-y+6x)]=6xy+7y+(8x-5xy+y-6x)=6xy+7y+8x-5xy+y-6x=(6xy-5xy)+(7y+y)+(8x-6x)=xy+8y+2x=x
6xy+7y+[8x-5xy+y-6x]=6xy+7y+8x-5xy+y-6x=(6xy-5xy)+(7y+y)+(8x-6x)=xy+8y+2x=xy+2(4y+x)=5-2=3再问:请问x=?y=
(1)把括号全打开得xy+2x+8y=xy+2(x+4y)=5-2=3(2)时针速度:30度/时分针速度:360度/时成直角时,分针与时针相差90度,7:00时相差210度,(210-90)÷(360
x+2xy+y分之2x-xy+2y=[2(x+y)-xy]/[(x+y)+2xy]=(12-8)/(6+16)=4/22=2/11
你确定没写错题目?后面的式子一约就变成前面的式子了,答案也是8/xy再问:怎么个约法?再答:y/xyyy约掉剩下1/x
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把第一个式子分开来看,x的平方-8x+16+y的平方+6Y+9=0,然后就有两个完全平方了,(x-4)的平方+(y+3)的平方=0然后可以得出x=4,y=-3,然后带进去就可以得出答案
1、x+y=8xy=6求x²+3xy+2y²/x²y+2xy²的值.x²+3xy+2y²/x²y+2xy²=(x+2y)
(5xy+4x+7y)+(6x-3xy)-(4xy-3y)=5xy+4x+7y+6x-3xy-4xy+3y=(5xy-3xy-4xy)+(4x+6x)+(7y+3y)=-2xy+10x+10y=-2x
∵A=8x²y-6xy²-3xy,B=7xy²-2xy+5x²y ∴C=3(A+B) =3(8x²y-6xy²-3xy+7xy²
已知xy+x+y=6则xy+x+y+1=(x+1)(y+1)=7=7×1因为x,y都是自然数(非负整数)所以x+1,y+1≥1所以只能x+1=7y+1=1即x=6,y=0或x+1=1,y+1=7即x=