3+8 = 11
(-2)-15+-2(-12-5) simplified is -2-15-2(-17)
if you simplify that even more, you get -2-15+34 (because -2(-17) is a positive 34).
then, -2-15 is -17 and then you add the 34 which gets you a positive 17.
so 11 divided by 17 is about 0.647 (rounded)
