Răspuns :
a:4+b:4=5 (inmultim cu 4 pt a scapa de numitor)
=>a+b=5*4
=>a+b=20=>b=20-a
a-b=12
Inlocuim in a-b=12:
a-20+a=12
=>2a=12+20
=>2a=32
=>a=32:2
=>a=16
b=20-a
=>b=20-16
=>a=4
Proba:
a-b=16-4=12
a+b=16+4=20
=>a+b=5*4
=>a+b=20=>b=20-a
a-b=12
Inlocuim in a-b=12:
a-20+a=12
=>2a=12+20
=>2a=32
=>a=32:2
=>a=16
b=20-a
=>b=20-16
=>a=4
Proba:
a-b=16-4=12
a+b=16+4=20