a+b+c+d=45
(a+2)=(b-2)=c*2=d:2
.....................................
a=? b=? c=? d=?
a=c*2-2....=> a=2c-2
b=c*2+2...=> b=2c+2
d=c*2*2....=> d= 4c
(2c-2)+(2c+2)+c+4c=45
9c-2+2=45
9c=45
c=45:9
c=5
a=5*2-2
a=10-2
a=8
b=5*2+2
b=10+2
b=12
d=5*4
d=20
8+12+5+20=
20+5+20
=25+20
=45