(15-40)+(87-30)
-25+57
32 total points
answer:
to my knowledge it's, 65
because 4x+20y=-36,so ( 4x+20y)/2=2x+10y=-18
(2x+10y)-(2x+5y)=-18-18
5y=-36
then y=-7.2
because 2x=18-5y
so x=(18-5y)/2=(18-5*(-7.2)）/2=27
