If `2[{:(3,4),(5,x):}]+[{:(1,y),(0,1):}]=[{:(7,0),(10,5):}]`, find (x-y).

Explanation

We have
`2[{:(3,4),(5,x):}]+[{:(1,y),(0,1):}]=[{:(7,0),(10,5):}]`
`implies" "[{:(6,8),(10,2x):}]+[{:(1,y),(0,1):}]=[{:(7,0),(10,5):}]`
`implies" "[{:(6+1,8+y),(10+0,2x+1):}]=[{:(7,0),(10,5):}]`
`implies" "2x+1=5" and "8+y=0`
[comparing the corresponding elements]
`implies" "x=2" and "y=-8.`
`implies" "(x-y)=2-(-8)=10.`