Răspuns :
[tex]21-7x=7\\
7x=21-7\\
7x=14\\
x=14/7\\
x=2\\\\
Proba:21-7*2=21-14\\
~~~~~~~~~~~~~~~~~~~~~~~~=7[/tex]
Rezolvare:
21-7x=7
7x=21-7
7x=14
x=14:7
[tex]x=\boxed{2}[/tex]
Proba:21-7*2=7
21-14=7
21-7x=7
7x=21-7
7x=14
x=14:7
[tex]x=\boxed{2}[/tex]
Proba:21-7*2=7
21-14=7