Răspuns :
Inmultim cu 8 paranteza
24 + 8a = 72
8a = 72 - 24
8a = 48
a = 48:8
a = 6
8•(3+a)= 72
(8•3)+(8•a)= 72
24+8a= 72
8a= 72-24
8a= 48
a= 48/8
a= 6
Verificare:
8•(3+6)= 72
8• 9=72
72=72 adevărat
(8•3)+(8•a)= 72
24+8a= 72
8a= 72-24
8a= 48
a= 48/8
a= 6
Verificare:
8•(3+6)= 72
8• 9=72
72=72 adevărat