已知x y=-4,xy=2,求根号下x分之y 根号下y分之x
来源:学生作业帮助网 编辑:作业帮 时间:2024/08/17 02:25:37
![已知x y=-4,xy=2,求根号下x分之y 根号下y分之x](/uploads/image/f/4226174-62-4.jpg?t=%E5%B7%B2%E7%9F%A5x+y%3D-4%2Cxy%3D2%2C%E6%B1%82%E6%A0%B9%E5%8F%B7%E4%B8%8Bx%E5%88%86%E4%B9%8By+%E6%A0%B9%E5%8F%B7%E4%B8%8By%E5%88%86%E4%B9%8Bx)
x-xy=8(1)xy-y=-9(2)则有(1)-(2):X-XY-XY+Y=X+Y-2XY=8-(-9)=17
x2-xy=-3①,2xy-y2=-8②,①×2+②×3得:2x2-2xy+6xy-3y2=-6-24=-30,则2x2+4xy-3y2=-30.
1.2(Xy+Xy)-3(Xy-xy)-4Xy=2*2xy-0-4xy=4xy-4xy=02.1/2ab-5aC-(3acb)+(3aC-4aC)=1/2ab-5ac-3acb-ac=1/2ab-6a
∵x2-xy=7,2xy+y2=4,∴原式=(x2-xy)+(2xy+y2)=7+4=11,故答案为:11
-xy(x^2y^5-xy^3-y)=-(xy^2)^3+(xy^2)^2+xy^2=-(-2)^3+4-2=8+4-2=10
原式=3xy+6y-xy+6x=2xy+6(x+y)=2*(-2)+6*4=24-4=20
因为x-y=4xy所以x-2xy-y=2xy2x+3xy-2y=11xyx-2xy-y分之2x+3xy-2y=5.5
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
1、已知2x²+xy=10,3y²+2xy=6,求4x²+8xy+9y²的值为?分析:通过观察,可以把8xy拆成2xy+6xy,分别于剩余的两项组合,并提取公因
(1)∵xy+x=-1①,xy-y=-2②,∴①-②得x+y=1;(2)先把xy+x=-1,xy-y=-2的值代入代数式,得原式=-x-[2y-1+3x]+2[x+4]=-x-2y+1-3x+2x+8
把已知两式相加结果为13
答案是3/2你是不是把分母打错了教你个方法因为上下是齐次的直接令x=3y=2带入就行
3(xy+2y)-(xy-6x)=3xy+6y-xy+6x=2xy+6(x+y)=2×(-2)+6×4=-4+24=20
xx+2xy-yy=-3两式相加即可
∵x-y=4xy,∴2x+3xy-2yx-2xy-y=2(x-y)+3xyx-y-2xy=8xy+3xy4xy-2xy=112.故答案为:112.
xy+1/xy>=2√(xy*1/xy)=2(当xy=1/xy即xy=1时取等号)x/y+y/x>=2√(x/y*y/x)=2(当x/y=y/x即x=y取等号)当x=y=1时可以同时满足两项的等号要求
3xy=2x+3y+5(3y-2)(x-1)=7所以3y-2=7x-1=1得y=3x=2xy=6或3y-2=1x-1=7得y=1x=6xy=6所以xy=6
根号(Y/X)+根号(X/Y)=根号(XY)/X+根号(XY)/Y=根号(xy)*(1/x+1/y)=根号3*(x+y)/xy=根号3*(-6)/3=-2根号3
原式=-xy²(x²y^4-xy²-1)∵xy²=-2原式=2((-2)²-(-2)-1)=10