若x+y=5,xy=1,则2x2+2y2﹣10=_________.
举一反三
- 分解因式()x()3()y()-()2()x()2()y()2()+()xy()3()正确的是A.()xy()(()x()+()y())()2()B.()xy()(()x()2()﹣()2()xy()+()y()2())()C.()xy()(()x()2()+2()xy()﹣()y()2())()D.()xy()(()x()﹣()y())()2
- (5). 由随机事件的分解性质,事件 \( \{XY=2\} \) 等价于( )。 A: \( \{X=1,Y=2\} \) B: \( \{X=2,Y=1\} \) C: \( \{X=1,Y=2\}\cap \{X=2,Y=1\} \) D: \( \{X=1,Y=2\}\cup \{X=2,Y=1\} \)
- 设f(x,y)=x[sup]2[/]-y,则f(xy,x+y)=( )。 A: x<sup>2</sup>-x-y B: x<sup>2</sup>y<sup>2</sup>-x-y C: x+y-x<sup>2</sup>y<sup>2</sup> D: (x+y)<sup>2</sup>-xy
- 已知|x|=3,|y|=2,xy<0,则x+y=________.
- 已知f(x+y,xy)=x^2+y^2,则f(x,y)=()