Answer:
8-(-8) = 8+8
8-8 = 8+(-8)
-8-(-8) = -8+8
-8-8 = -8+(-8)
10-9 = 10+(-9)
10-(-9) = 10+9
Step-by-step explanation:
Remember that if the signs are equal +,+ or -,- , they are positive (+)
if the signs are different like +,- or -,+ then they are negative (-)
I think it is Y = 0 because you never told me how to slove it
for all 
, you can write as a first step
, you can eliminate both factors of 
in the numerator and denominator to end up with 
.