已知| x+y-10| +(2x-y-15)^2=0,求x-5y+3的值

已知| x+y-10| +(2x-y-15)^2=0,求x-5y+3的值
已知| x+y-10| +(2x-y-15)^2=0,求x-5y+3的值

已知| x+y-10| +(2x-y-15)^2=0,求x-5y+3的值
因为平方大于等于零,绝对值也大于等于零,所以
| x+y-10| =0
(2x-y-15)^2=0
所以x+y-10=0
2x-y-15=0
x=25/3,y=5/3
所以代入,求得x-5y+3=3

两个大于等于0的数相加等于0
必须两者都等于0
x+y=10
2x-y=15
x=25/3
y=5/3
x-5y+3=3

| x+y-10| +(2x-y-15)^2=0
所以x+y-10=0,2x-y-15=0
解得x=25/3,y=5/3
x-5y+3
=25/3-5/3*5+5
=3

| x+y-10|大于等于0
(2x-y-15)^2大于等于0
所以| x+y-10| +(2x-y-15)^2大于=0,只当| x+y-10| 和(2x-y-15)^2都等于0时,式子| x+y-10| +(2x-y-15)^2=0成立
所以知| x+y-10| =0且(2x-y-15)^2=0
x=25/3,Y=5/3
所以x-5y+3=3

| x+y-10| >=0 (2x-y-15)^2>=0,
且| x+y-10| +(2x-y-15)^2=0,
所以x+y-10=0
2x-y-15=0
所以X=25/3,Y=5/3
x-5y+3=3