Răspuns :
a+b+c+d=18 a+a+4+(a+2)/2+2a+4=18
4a+(a+2)/2=10
a+2=b-2=2c=d/2
a+2=b-2,a+4=b 9a=18,a=2,b=a+4=6,c=2,d=8
=====
A+2=2C,C=(a+2)/2 VERIFICARE 2+6+2+8=18
=======
a+2=d/2.d=2a+4
=======
4a+(a+2)/2=10
a+2=b-2=2c=d/2
a+2=b-2,a+4=b 9a=18,a=2,b=a+4=6,c=2,d=8
=====
A+2=2C,C=(a+2)/2 VERIFICARE 2+6+2+8=18
=======
a+2=d/2.d=2a+4
=======