Respuesta :
hmm
let's try some numbers
we have 3 scenarios
x>y
x=y
x<y
x>y
x=-1 and y=-2
x-y=-1-(-2)=-1+2=1
it's positive when x>y
x=y
x=-1, y=-1
-1-(-1)=-1+1=0
nope
x<y
x=-2 and y=-1
-2-(-1)=-2+1=-1
nope
x-y is positive when 0>x>y
let's try some numbers
we have 3 scenarios
x>y
x=y
x<y
x>y
x=-1 and y=-2
x-y=-1-(-2)=-1+2=1
it's positive when x>y
x=y
x=-1, y=-1
-1-(-1)=-1+1=0
nope
x<y
x=-2 and y=-1
-2-(-1)=-2+1=-1
nope
x-y is positive when 0>x>y