xy的新计算*,x*y等于ax的y次方 y 1,1*2
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x加y的平方等于9,x减y的平方等于5两式相减得:4xy=9-5=4xy=1
x*y=2xy-1,(1*3)*(-2)=(2×1×3-1)*(-2)=5*(-2)=2×5×(-2)-1=-20-1=-21
由题意知:2a+b+2*1=7-3a+3b+(-3)*3=3即2a+b=5(1)-3a+3b=12(2)(2)÷(-3)得:a-b=4(3)(1)+(3)得:3a=9,a=3将a=3带入(3)得:b=
根据题意得2a+b+2=7-3a+2b-3=1∴a=6/7b=23/7∴x*y=6x/7+23y/7+xy∴1/3*6=2/7+138/7+2=22
∵x*y=ax+by+c∴1*2=a+2b+c=9(x=1,y=2)(-3)*3=-3a+3b+c=6(x=-3,y=3)0*1=b+c=2(x=0,y=1)∴a=2,b=5,c=-3∴-2*5=-2
X☆y=xy-x-y计算:(-1)☆(-½)=(-1)×(-1/2)-(-1)-(-1/2)=1/2+1+1/2=2;三分之二☆(-3)=(2/3)×(-3)-2/3-(-3)=-2-2/3
{9=1*2=a+2b+c{6=(-3)*3=-3a+3b+c{2=0*1=b+c解这个3元一次方程组得到a=2,b=5,c=-3然后用x*y=2x+5y-32*(-7)=2*2-5*7-3=-3
(x^2-xy)/(xy^2)·y/(y-x)=x(x-y)/(xy^2)·y/(y-x)=(x-y)/(y^2)·y/(y-x)=-1/y再答:二十年教学经验,专业值得信赖!如果你认可我的回答,敬请
y/(x²-xy)+2/(y-x)-x/(y²-xy)=[y²+2(-xy)+x²]/(x²y-xy²)=(x-y)²/[(x-y
x*y=x-2xy+3y,2a*b-(-2a)*(-3b)=2(a-2ab+3b)-(-2a-12ab-9b)=2a-4ab+6b+2a+12ab+9b=4a+8ab+15
这题少括号了吧.
【x²+xy/(x-y)】/【xy/(x-y)】=【x²(x-y)/(x-y)+xy/(x-y)】/【xy/(x-y)】={【x²(x-y)+xy】/(x-y)}/【xy
原式=x^2/xy-y^2/xy-[(x-y)y]/[(y-x)x]=x/y-y/x+y/x=x/y.
因为{3x-2y=4,ax+by=7}与{2ax-3by=19,5y-x=3}有同解所以它们与方程组3x-2y=4①5y-x=3②有相同解①+②*3得13y=13所以y=1,将其代入②得x=1将x=y
原式=-x^2+2xy-y^2-2xy+6x^2+6y^2-3xy=5x^2-3xy+5y^2
|x-y|=4,xy=-3(x+y)^2=(x-y)^2+4xy=14-12=2x+y=根2,-根2xy^2+x^2y=xy(x+y)=-3根2,3根2再问:(x+y)^2=(x-y)^2+4xy=1
(2X的平方Y-XY)乘以3XY=6X³Y²-3X²Y²
解析:(-3x的2次方y).(3分之一XY的2次方)=-3×1/3x³y³=-x³y³有什么不明白的可以继续追问,
解(x-y)/(xy-y²)=(x-y)/y(x-y)=1/y