x y=2m 7 x−y=4m−3
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N-M=X的平方+2XY+Y的平方-X的平方+2XY-Y的平方=4XY所以4XY=N-M
解xy互为相反数y=-x代入2y-x=-72y+y=-73y=-7所以y=-7/3x=7/3代入2x-y=4m+3,14/3+7/3=4m+34m+3=7m=1再问:某工厂有28名工人,生产螺母和螺栓
3x+2y=m+14x+y=m解得5x=m-1,x=(m-1)/5,y=(4+m)/5(m-1)/5
因为x-y=4xy所以x-2xy-y=2xy2x+3xy-2y=11xyx-2xy-y分之2x+3xy-2y=5.5
(-3x^y+2xy)-(4x^+xy)=-3x^y+2xy-4x^-xy=-3x^y+xy-4x^所以填上-3x^y+xy-4x^
因为x属于z,z代表整数又因为xy0,y
原式=[4(x+y)-2xy]分之[(x+y)+xy]=[4(3xy)-2xy]分之[(3xy)+xy]=10xy分之2xy=5分之1
x+2y=3m+53x-4y=4m-15第一个式子乘以2加第二个式子得:5x=10m-5x=2m-1再代入x+2y=3m+5得y=m/2+3所以x=2m-1y=m/2+3
(4xy+12y)+[7x-(3xy+4y-x)]=4xy+12y+7x-3xy-4y+x=xy+8x+8y=xy+8(x+y)=(-2)+8*3=-2+24=22
因为y=3xy+x,所以x-y=-3xy,当x-y=-3xy时,2x+3xy−2yx−2xy−y=2(x−y)+3xy(x−y)−2xy=2(−3xy)+3xy−3xy−2xy=35.
M-(2x^2-3xy+xy^2)(-xy)=(2x^2y+xy^2)(x-2y)M=(2x^2y+xy^2)(x-2y)-(xy)(2x^2-3xy+xy^2)=2x^3y-4x^2y^2+x^2y
∵x-y=4xy,∴2x+3xy-2yx-2xy-y=2(x-y)+3xyx-y-2xy=8xy+3xy4xy-2xy=112.故答案为:112.
M=(2x^2y+xy^2)(x-2y)-(2x^2-3xy+xy^2)(-xy)很简单啊.
{(x,y)|xy
设另一因式是A4xy-4x²-y²-m=A(1-2x+y)则x=1,y=1时,1-2x+y=0则右边A(1-2x+y)=0所以左边也等于0所以4xy-4x²-y²
2x+y=2m+7①x-y=4m-1②①+②,得:3x=6m+6x=2m+2代入②中,得:2m+2-y=4m-1y=(2m+2)-(4m-1)=3-2m∵x、y都是正数∴x>0,y>0即2m+2>0,
x-y=3》》x=y+3代入方程组2x+7y=m+1.13x+4y=m.22y+6+7y=m+13y+9+4y=m2y+6+7y=3y+9+4y+1y=2x=5m=23再问:���ǽ���Ԫһ�η��
xy>0得x,y同号又因为x+y
3x-y=m-22x+4y=3mx+y=03(x+y)-4y=m-24(x+y)-2x=3m-4y=m-2-2x=3m-4y=m-2(1)-4x=6m(2)(1)+(2)-4(x+y)=7m-27m-