Y=(X-8)[100-10(X-10)](X-8)(200-10X)-10X²+280X-1600=-10(X-14)²+360最后的360是怎么算出来的.是怎么从-10X²+280X-1600 算出来的?这是二次函数

y+y+x=10,x+y+x=8,y=?,x=? X+Y-8X+10Y+41=O,求X/Y-Y/X的值 X+Y=7(100X+Y)-(10Y+X)=(10Y+X)-(10X+Y) (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 若x-y不等于0,2x-3y=0,则分式(10x-11y)/(x-y)的值是（）?(10x-11y)/(x-y) =[(8x-8y)+(2x-3y)]/(x-y) =8为什么8X-8Y=8？(10x-11y)/(x-y)=[(8x-8y)+(2x-3y)]/(x-y)=8+(2x-3y)]/(x-y)=8+0=8 {x-y=100 {12%x-10%y=100 x+y=94 8x+10y=834 x+y=10;8x+6y=66 x+y=10 x-y=8 x+y=8,x+z=10,y+x=12,那么x+2y+x=? 10X+Y+1/3Z=10Y+X 10X+Y+2/3Z=100X+Y 3(2X+Y)+(2(2x-Y)=6 (8X+4y)-(10X-5Y)=2 (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 若x+y-8x-10y+41=0,求x／y+y／x的值 已知x²+y²-8x-10y+41=0,则x/y-y/x的值为 已知x²+y²-8x-10y+41=0,求x/y-y/x的值 x²+y²-8x-10y+41=0,求x/y-y/x的值. 1 三元的 4x+8y+10z=100x+y+z=152 二元的 1.5x+2x=2101.5(x+y)=210