Răspuns:
Explicație pas cu pas:
4. a+b+c+d=80 (inlocuiesti litera cu egalul sau)
b×3+b+b+10+(b×3+6)=80 (b×3=3b)
3b+b+b+10+3b+6=80
8b+16=80
8b=80-16
8b=64
b=64:8 b=8
a=8×3 a=24
c=8+10 c=18
d=(8×3)+10 d=34
5. 2d=108 d=108:2 d=54
c-54=325 c=325+54 c=379
b+379=399 b=399-379 b=20
a+20+379+54=1000 a=1000-453 a=547