已知x,y为整数,且满足x²+3xy+2y²+2x+4y=-1求xy
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(x+y)=(8/x+2/y)(x+y)=10+(8y/x)+2x/y)x/y>0,y/x>0所以8y/x+2x/y≥2√(8y/x)*2x/y)=8所以(x+y)≥10+8=18x+y≥18最小值是
x+y=8,x²-2xy+y²-4x+4y+4=0,即(x-y)²-4(x-y)+4=0,(x-y-2)²=0x-y-2=0x=5,y=3长方形的面积=5*3=
∵-2<-2<-1,1<3<2,∴x应在-2和2之间,则x=-1,0,1.故答案为:-1,0,1.
xy=6/(x+y)xy(x+y)=6,已知x和y是整数,则xy和(x+y)也是整数,而6=2*3=1*6当xy=3时,x+y=2,无整数解当xy=1时,x+y=6,无整数解当xy=6时,x+y=1,
将xyz+xy+yz+xz+x+y+z-2变形xyz+xy+y+xz+z+yz+x-2=xyz+y(x+1)+z(x+1)+yz+x-2=xyz+(y+z)(x+1)+yz+x-2=yz(x+1)+(
x=24,y=8,x+y=32或x=54,y=2,x+y=56根据x>y(x+y)+(x+xy-y)+x/y=243x/y无余数故有正整数kx=ky(x+y)+(x+xy-y)+x/y=243代入x=
周长16所以2(X+Y)=16X+Y=8(1)即(X-Y)²-4(X-Y)+4=0(X-Y-2)=0X-Y-2=0(2)所以X=5,Y=3.所以面积=XY=15
x+2y=3ky-3x=-2解方程组得x=(3k+4)/7y=(9k-2)/7因为y>-1且x<1(9k-2)/7>-1(3k+4)/7<1-5/9
x,y分别表示根号5的整数部分和小数部分因此有x=2,y=根号5-2axy+by^2=y(ax+by)=(根号5-2)(ax+by)=1=>ax+by=根号5+2=>2a+b*(根号5-2)=根号5+
-√2≈-1.4几,√3≈1.7几所以X=-10或者1
∵2x+2x2−1=2x−1,∴根据题意,得x-1=±1或±2,则x=2或0或3或-1.又x≠±1,则x=0或2或3.
∵1+x−(y−1)1−y=0,∴1+x+(1−y)1−y=0,∴x+1=0,y-1=0,解得x=-1,y=1,∴x2011-y2011=(-1)2011-12011,=-1-1,=-2.故答案为:-
xy-3x-5y+15=92(x-5)(y-3)=92=1×92=2×46=4×23所有整数对(x,y)的组数为12
根号2的相反数是-根号2大约是-1.14根号3大约是1.7...X为整数所以X可以是-101
由x2+2y+2y=17-42,得到x2+2y=17,y=-4,解得:x=±5,则x+y=1或-9.故答案为:1或-9
x-y-x^2+2xy-y^2+2=0(x-y)-(x-y)^2+2=0(x-y)^2-(x-y)-2=0(x-y-2)(x-y+1)=0x=2+yx=y-12x+2y=204+2y+2y=20y=4
先把它配成(X-Y)^2-2(X-Y)-8=0(X-Y+2)(X-Y-4)=0得到X-Y+2=0或者X-Y-4=0然后联立X+Y=8得到两个方程组,解出两组解,最后检验一下是否都符合题意满意的话望采纳
(x-y)²-3(x-y)-4=0①2(x+y)=16x+y=8②由①②得x=6cmy=2cm所以面积S=6*2=12平方厘米
X+Y=8x^2-2y+y^2-x+y-2=0,x^2-y+y^2-x-2=0,(X+Y)^2-2XY-(X+Y)-2=064-2XY-8-2=0XY=27
x(平方)-2xy+y(平方)-2x+2y-8=0(x-y)平方-2(x-y)-8=0(x-y-4)(x-y+2)=0因此x-y-4=0或x-y+2=0长方形的周长为16cm它的长为x宽为y,则x+y