Răspuns:
1. a=27, b=4•a, a+b=?
2. a=13, b=4•a, b-a=?
3. a=b+5, b=20, c=4•a, a+b+c=?
4. a=4•b, b=x, a+b=90; a=?, b=?
5. a=b+39, b+a=117, b=?
6. a=b+17, b=20, a+b+c=101, c=?
7. b=x•4, 3•x=72, a=x, X=?
