Răspuns :
a+b+c+d=70
a-x=2 => a=2+x
b-x=7 => b=7+x
c-x=12 => c=12+x
d-x=17 => d=17+x
inlocuim
2+x+7+x+12+x+17+x=70
4•x+38=70
4•x=70-38
4•x=32
x=32:4
x=8
a=2+8=10
b=7+8=15
c=12+8=20
d=17+8=25
2+7+12+17=38
70-38= 32
32:4(deoarece sunt 4 numere)=8
Verificare : 10+15+20+25=70
#destiny
70-38= 32
32:4(deoarece sunt 4 numere)=8
Verificare : 10+15+20+25=70
#destiny