So |x+7/2|+|y-4/3|=0.
Because the sum of non-negative numbers is 0,
So |x+7/2| and |y-4/3| are all equal to 0.
That is, x+7/2=0 y-4/3=0.
So x =-7/2 and y = 4/3.
So 2x+y=- 17/3.
The second question should be discussed in categories.
1。 When a, b and c are all greater than 0
2。 a & gt0,b & gt0,c & lt0
3.a & gt0b & lt; 0,c & lt0
And so on, there are many situations, you should understand?