求证(10x+y)[10x+(10-y)]=100x(x+1)+y(10-y)恒为等式1 求证：(10x+y)[10x+(10-y)]=100x(x+1)+y(10-y)恒为等式2 已知a、b、c是有理数,且a+b+c=1,a²+b²+c²-ab-bc-ca=0,则a、b、c三者之间的关系是______

求证,不论x.y为何有理数,x²+y²-10x+8y+45的值均为正数 求证：不论x、y为何有理数,x²+y²-10x+8y+45的值均为正数 X＞0,Y＞0,X+Y=10,求证：XY≤25. 求证：(10x+y)[10x+(10-y)]=100x（x+1）+y（10-y)为恒等式,并利用此恒等式计算1998X1992 (x+y)²-10(x+y)+25 y+10x=x+y+9 10y+x=y+10x+27 已知y>x>e,求证：x^y>y^x (x+y)/6+(x-y)/10=1,(x+y)/6-(x-y)/10=5 {6/x+y+10/x-y=30 6/x+y-10/x-y=-1 25(x-y)*2+10(y-x)+125（x-y)^2+10(y-x)+1 [2X+(Y-10)][2X-(Y-10)]-(3X+Y)(3X-Y) x+y=20,x-y=10,y= (x+5y)^+(2x+10y)(3x-y)+(3x-y)^ (x+5y)²-(2x+10y)(3x-y)+(3x-y)² 已知|x|+x+y=10,|y|+x-y=12,求x+y的值 已知|x|+x+y=10,x+|y|-y=12,求x、y的值 已知/x/+x+y=10,/y/+x-y=12.求x+y的值 X+Y-8X+10Y+41=O,求X/Y-Y/X的值