x²-x-x²+y=-2
x-y=2
x^2+y^2/2-xy
=(x²-2xy+y²)/2
=(x-y)²/2
=4/2
=2
已知x(x-1)-(x^2-y)=-2,求x^2+y^2\/2-xy的值 有分!
x^2-x-x^2+y=-2 y-x=2 所以x-y=2 (x^2+y^2)\/2-xy =(x^2-2xy+y^2)\/2 =(x-y)^2\/2 =4\/2 =2
已知x(x-1)-(x^2-y)=-2,求x^2+y^2\/2-xy的值
x（x-1）-（x^2-y）=-2 x²-x-x²+y=-2 x-y=2 x^2+y^2\/2-xy =(x²-2xy+y²)\/2 =(x-y)²\/2 =4\/2 =2
已知x(x-1)-(x的2次方-y)=-2,求(x的2次方+y的2次方\/2)-xy
此题应为：已知x（x-1)-(x^2-y)= -2 求（x^2+y^2)\/2-xy的值。解：由 x(x-1)-(x^2-y)= -2 展开 得 x^2-x-x^2+y= -2 x-y=2 所以 (x^2+y^2)\/2-xy =x^2\/2+y^2\/2-2xy\/2 =(x-y)^2\/2 将x-y=2整体代入 得 =(x-y)^2\/2 =4\/2 =2 ...
若x(x-1)-(x^2-y)=-2 求(x^2+y^2)\/2 -xy的值
1）因为x(x-1)-(x^2-y)=-2,所以x^2-x-x^2+y=-2,所以x-y=2,所以[(x^2+y^2)\/2 ]-xy =(x^2+y^2)\/2-2xy\/2 =(x-y)^2\/2 =2^2\/2 =2;2）6^(m+n)=6^m*6^n=3*5=15;3）因为x^2-2x+y^2+6y+10=0，所以(x^2-2x+1)+(y^2+6y+9)=0,所以(x-1)^...
已知x(x-1)-(x^2-y)=-2,求x^2+y^2除以2-xy的值
结果=2 过程如图 如果你认可我的回答，请点击“采纳答案”，祝学习进步！手机提问的朋友在客户端右上角评价点【满意】即可
已知x(x减1)减(x的平方减y)等于负2,求2分之x平方加y的平方减xy的值
x(x-1)-(x^2-y)=-2 x^2-x-x^2+y=-2 x=y+2 (x\/2)^2+y^2-xy =((y+2)^2\/4)+y^2-(y+2)y =y^2-4y+4
已知X(X-1)-(X²一y)=-2,求X²+y²\/2-Xy的值
X（X-1）-（X²一y）=-2 x²-x-x²+y=-2 ∴-x+y=-2 即x-y=2 (x²+y²)\/2-xy =1\/2(x²+y²-2xy)=1\/2(x-y)²=2²÷2 =2
已知:x(x-1)-(x^2-y)=-4,求x^2+y^2\/2-xy的值
希望帮得到你O(∩_∩)O哈！
已知x(x-1)-(x²-y)=-2,求x²+y²\/2-xy的值
答案为2。把已知的括号打开化简之后，可以得出x-y=2，再把所求的式子通分，分子为(x-y)^2,带入之后旧的出答案了。
已知x(x-1)-(x2-y)=-2,求x2+y22?xy的值
∵x（x-1）-（x2-y）=-2，∴x2-x-x2+y=-2，∴x-y=2，∴x2+y22-xy=x2+y2?2xy2=(x?y)22=2．
