若|a-1/2|+(b+1/3)²=0 1.求a、b的值 2.求代数式4a²-2ab-b²的值
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![若|a-1/2|+(b+1/3)²=0 1.求a、b的值 2.求代数式4a²-2ab-b²的值](/uploads/image/z/4001495-23-5.jpg?t=%E8%8B%A5%7Ca-1%2F2%7C%2B%EF%BC%88b%2B1%2F3%29%26%23178%3B%3D0+1.%E6%B1%82a%E3%80%81b%E7%9A%84%E5%80%BC+2.%E6%B1%82%E4%BB%A3%E6%95%B0%E5%BC%8F4a%26%23178%3B-2ab-b%26%23178%3B%E7%9A%84%E5%80%BC)
若|a-1/2|+(b+1/3)²=0 1.求a、b的值 2.求代数式4a²-2ab-b²的值
若|a-1/2|+(b+1/3)²=0 1.求a、b的值 2.求代数式4a²-2ab-b²的值
若|a-1/2|+(b+1/3)²=0 1.求a、b的值 2.求代数式4a²-2ab-b²的值
1.
|a-1/2|+(b+1/3)²=0
|a-1/2|>=0
(b+1/3)²>=0
所以
a-1/2=0,b+1/3=0
a=1/2,b=-1/3
2.
4a²-2ab-b²
=4*(1/2)^2-2*1/2*(-1/3)-(1/3)^2
=1+1/3-1/9
=11/9
绝对值和平方大于等于0,相加等于0,若有一个大于0,则另一个小于0,不成立。
所以两个都等于0
所以a-1/2=0,b+1/3=0
a=1/2,b=-1/3
4a²-2ab-b²
=1+2/3-1/9
=14/9
|a-1/2|+(b+1/3)²=0,所以a-1/2=0,b+1/3=0,得到a=1/2,b=-1/3,所
4a²-2ab-b^2=4*(1/2)^2-2*1/2*1/3-(-1/3)^2=11/9