如果x y=2那么4-x y=多少
来源:学生作业帮助网 编辑:作业帮 时间:2024/10/03 04:30:07
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
y²=12y=±√12=±2√3xy=√6×(±2√3)=±2√18=±6√2于是4/xy=4/(±6√2)=±√2/3再问:你4/(±6√2)那里是怎么化简的,可以写下过程吗。。再答:4/
x+y=2,y=2-x,xy=x(2-x)若x=0,2,xy=0若2>x>0,2>xy>0x2,xy
x的平方+3xy+2y的平方=(x的平方+xy)+(xy+y的平方)+(xy+y的平方)=3-2-2=-1
2#3=2*3/(2+3)=6/56/5#4=[(6/5)*4]/(6/5+4)=12/132#3#4=12/13
x²y-xy²=xy(x-y)=3×2=6再问:怎样变为xy(x-y)再答:提取公因式x²y=(xy)×(x)xy²=(xy)×(y)都有因式xy,可以提取出来
∵2x+y=4,xy=3,∴2x2y+xy2=xy(2x+y)=3×4=12.故答案为:12
(1)因为x^2+xy=2,y^2+xy=7所以x^2+2xy+y^2=(x^2+xy)+(y^2+xy)=2+7=9(2)因为a^2-ab=3,b^2+ab=2所以a^2+b^2=(a^2-ab)+
x²+xy=3………………………①y²+xy=-2……………………②①+②得:x²+2xy+y²=1(x+y)²=1x+y=±1∴x²+3x
2(x+xy)-[(xy-3y)-x]-(-xy)=2x+2xy-xy+3y+x+xy=3x+3y+2xy=3(x+y)+2xy=3*(-2)+2*3=0
1/x-1/y=2(y-x)/xy=2y-x=2xy(3x+5xy-3y)/(x-xy-y)=[5xy-3(y-x)]/[-xy-(y-x)]=(5xy-6xy)/(-xy-2xy)=-xy/-3xy
x^2+2xy+y^2=(x^2+xy)+(xy+y^2)=2+7=9
2x+3y-3xy+4xy-3x-4y+7=(2x-3x+3y-4y)+4xy-3xy+7=(-x-y)+xy+7=-(x+y)+xy+7=-4-1+7=2
如果,那么x²+2xy+y²=x²+xy+(y²+xy)=2+7=9如果a²-ab=3,b²+ab=2,那么a²+b²=
x²+xy=2,y²+xy=7(x²+xy)+(y²+xy)=2+7x²+2xy+y²=9a²-ab=3,b²+ab=2
X的平方+XY=2X的平方=2-XYY的平方+XY=7Y的平方=7-XYX的平方+2XY+Y的平方=2-XY+2XY+7-XY=9
=xy(y-2)+2(y-2)=(y-2)(xy+2)
x^2+y^2=x^2+y^2+2xy-2xy=(x+y)^2-2xy=a^2-2·(1/4a)=a^2-a/2【若你想表示的实际是:xy=1/(4a),则结果为:a^2-1/(2a)】
2A-3B=2(3x²-xy+y²)-3(2x²-3xy-2y²)=6x²-2xy+2y²-6x²+9xy+6y²=7x