su光域网ies文件下载:初一数学题
来源:百度文库 编辑:神马品牌网 时间:2024/08/28 06:44:44
麻烦帮我算一下,今天中午就要——
若x*x-2x+y*y+6y+10=0,则x+y=
若3的m次方=6,3的n次方=2,则3的2m-3n次方=
若x*x-2x+y*y+6y+10=0,则x+y=
若3的m次方=6,3的n次方=2,则3的2m-3n次方=
x*x-2x+y*y+6y+10=0
x^2-2x+1+y^2+6y+9=0
(x-1)^2+(y+3)^2=0
所以(x-1)^2=(y+3)^2=0
x=1,y=-3
x+y=-2
2.
3^m=6,3^n=2
3^(2m-3n)
=(3^m)^2/(3^n)^3
=36/8
=9/2
(x*x-2x+1)+(y*y+6y+9)=0
(x-1)*(x-1)+(y+3)*(y+3)=0
x=1,y=-3 x+y=-2
3的2m-3n=3的2m次方/3的3n次方
=36/8=4
x+y=-2
x*x-2x+y*y+6y+10=0
(x-1)^2+(y+3)^2=0
x=1
y=-3
把10拆成1和9
3的m次方=6,3的n次方=2,则3的2m-3n次方=28
3^2m-3n
=(3^m)2-(3^n)3
=36-8
=28
x*x-2x+y*y+6y+10=0
可以转换为(X-1)*(X-1)+(Y+3)*(Y+3)=0
所以有(X-1)=0且(Y+3)=0
所以:X=1 Y=-3
3的m方=6 3的n次方=2
3的(2m-3n)次方=(3的2m次方)/(3的3n次方)=[(3的m次方)的2次方]/[(3的n次方)的3次方]=[6的2次方]/[2的3次方]=36/8=4.5