Răspuns :
Eu ti-o fac pe 2:
2.a+b+c=702
a=78
b=78x2
c=?
78+156+c=702/-78
156+c=624/-156
c=468
78+156+468=702
2.a+b+c=702
a=78
b=78x2
c=?
78+156+c=702/-78
156+c=624/-156
c=468
78+156+468=702
1. a+(b:2)=93 /×2 ---> 2a+b=186
a=b+72 2×(b+72)+b=186
2×b +144+b=186
3×b=186-144
b= 42:3
b= 14
a=14+72=86