Question

已知有理数x、y、z，且|x-3|+2|y+1|+7(2z+1)的2次方=0，求x+y+z的相反数

Answer 1

|x-3|+2|y+1|+7(2z+1)^2=0
因为|x-3|>=0，且2|y+1|>=0，且7(2z+1)^2>=0
所以x-3=0，2(y+1)=0，7(2z+1)^2=0
x=3，y=-1，z=-1/2
x+y+z=3/2
其相反数为-3/2

Answer 2

|x - 3| + 2|y + 1| + 7(2z + 1)² = 0
x = 3 , y = -1 , z = -1/2
x + y + z = 3/2
-(x + y + z) = -3/2

Answer 3

|x-3|+2|y+1|+7(2z+1)^2=0
=>
x-3=0 and y+1=0 and 2z+1=0
x=3 and y=-1 and z=-1/2
x+y+z= 3-1-1/2 = 3/2
x+y+z 的相反数 =-3/2