Question

x=2+4+6+...+288-144 la a2

Answer 1

2 (1+2+3+....144)-144^2=
facem Gauss 
1+2+3+...+144=
144*145/2

Bagam la loc in ecuatie

2*144*145/2 - 144^2=  simplificam 2 cu 2 si ramane
144*145-144^2=  dam factor pe 144
144(145-144)=
144*1=
144

Answer 2

X=2+4+6+...+288-144²=2(1+2+3+...+144)-144²=2*(144*145/2)-144²=144*145-144²=144*(145-144)=144*1=144