Answer:
C
Explanation:
Since it is only addition and subtraction, you can rearrange the order of the equations. This is what the three eqautions will look like after the arrangement:
1.6z + 8.3 z = ? (9.9z)
6.2y - 5.1y = ? (1.1y)
4.3x + 5.5x = ? (9.8x)
Then you just add and subtract.