以知x y=--4,xy=3,则x的2次方 y的2次方=多少
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由xy/(x+y)=2,∴xy=2(x+y)∵(-x+2xy-y)/(3x-5xy+3y)=(-x-y+4x+4y)/3x+3y-10x-10y)=(3x+3y)/(-7x-7y)=-3/7.
(xy-2y)+3x+5y=xy+3x+3y=-1+3*2=5
x+y=3,xy=14x+3xy+4y=4(x+y)+3xy=4x3+3x1=12+3=15祝学习进步,望采纳,不懂的欢迎追问.再问:怎么又是你啊。。。再问一道题:代数式x²+x+3的值为7
由,X/3+Y/4=1得y=4-4x/3.故求xy的最大值即求:xy=x(4-4x/3)=4x-4/3*x^2的最大值.根据抛物线性质易求得最大值即为顶点处.
(3x-4y+5xy)-(2x-3y)+5xy=3x-2x-4y+3y+5xy+5xy=x-y+10xy=3+4×10=43
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
√(3x+4)+(y-3)=0则:3x+4=0且y-3=0得:x=-4/3、y=3再问:为啥要这样做,请老师指点一下谢谢了再答:因为:√(3x+4)≥0、|y-3|≥0,则:√(3x+4)+|y-3|
16再问:我要过程再答:=x^3y^3z^3/xyz^2=(xy)^2z=16
(-3x^y+2xy)-(4x^+xy)=-3x^y+2xy-4x^-xy=-3x^y+xy-4x^所以填上-3x^y+xy-4x^
xdy=(y+xy)dxdy/y=((1+x)/x)dxln|y|=ln|x|+x+cy=±e^(ln|x|+x+c)其中c是常数再问:真还不理解我们是选择题:y=cxe^xy=c+x-x^2y=cs
x2+y2+3xy=(x+y)2+xy,∵x+y=4,xy=2,∴x2+y2+3xy=42+2=18.故答案为18.
3xy-[2xy-2(xy-2分之3xy)+xy]+3xy=6xy-[2xy-2xy+3xy+xy)=6xy-4xy=2xy=2×3×3分之1=2
2x-3*根号(xy)-2y=0(根号X-2根号Y)(2根号X+根号Y)=0根号X-2根号Y=0时X=4Y2根号X+根号Y=0时X=Y=0(不合题意,舍去)x2+4xy-16y2除以2x2+xy-9y
xx+2xy-yy=-3两式相加即可
(3x-4y+5xy)-(2x-3y-2xy)=3x-4y+5xy-2x+3y+2xy=x-y+7xy=4+7×(-2)=4-14=-10
(3x^2+2xy)/xy-(2x^2-xy)/xy=(3x^2+2xy-2x^2+xy)/xy=(x^2+3xy)/xy=x(x+3y)/xy=(x+3y)/y
∵x-y=4xy,∴2x+3xy-2yx-2xy-y=2(x-y)+3xyx-y-2xy=8xy+3xy4xy-2xy=112.故答案为:112.
一式乘以2加上2式乘以3=2(2x的平方+xy)+3(3y的平方+2xy)=4x的平方+8xy+9y=2*10+3*6=38
x²-3xy+4x=3,y²+xy-4y+7=0相加得x²-2xy+y²+4(x-y)+4=0(x-y)²+4(x-y)+4=0(x-y+2)=0,得
原式=4xy+8y+6x+2xy-5y-3x=6xy+3x+3y=6*3+3(x+y)=18-12=6