已知实数x、y满足：3（x3+y3+1）=（x-y+1)3，x²⁰¹⁴+y²⁰¹⁴=

10.已知线性变换-|||- ) (x)_(1)=2(y)_(1)+2(y)_(2)+(y)_(3) (x)_(2)=3(y)_(1)+(y)_(2)+5(y

3.已知两个线性变换-|||- ) (x)_(1)=2(y)_(1)+(y)_(3), (x)_(2)=-2(y)_(1)+3(y)_(2)+2(y)_(3)

已知函数 =(x)^3y+3(x)^2(y)^2-x(y)^3 ,则 =(x)^3y+3(x)^2(y)^2-x(y)^3 ( ) A =(x)^3y+3

3.已知两个线性变换-|||- ) (x)_(1)=2(y)_(1)+ (y)_(3) (x)_(2)=-2(y)_(1)+3(y)_(2)+2(y)_(3

[单选题]已知实数x,y，满足|x-3|+√（y-6）=0,则以x,y的值为两边长的等腰三角形的周长是A．12B．15C．12或15D．都不对

曲线y=(x-1 )3√x^2的凹区间为（ ）y=(x-1 )3√x^2y=(x-1 )3√x^2y=(x-1 )3√x^2y=(x-1 )3√x^2曲线的凹区

1.计算:(3x+y+2)(3x-y-2).2.已知(3x+y+2)(3x-y-2).求（a+b-c）²。3.设x>0,且(3x+y+2)(3x-y-2).求(

【题目】对随机变量X和Y,已知D(X)=2,D(Y)=3 cos(X,Y)=-1 ,计算cov（3X-2Y+1,X+4Y-3）.【题目】对随机变量X和Y,已知D

设_(1)=iint ((x)^3+(y)^3)de，_(1)=iint ((x)^3+(y)^3)de，_(1)=iint ((x)^3+(y)^3)de，其

已知两个线性变换： ) (y)_(1)=2(x)_(1)+(x)_(2) (y)_(2)=3(x)_(1)-(x)_(2)+2(x)_(3) (y)_(3)=