Răspuns :
Notez numarul cu ,,a "
[ ( 3 x a + 7 ) x 8 - 7 ] : 5 = 29
( 3 x a + 7 ) x 8 - 7 = 29 x 5 = 145
( 3 x a + 7 ) x 8 = 145 + 7 = 152
3 x a + 7 = 152 : 8 = 19
3 x a = 19 - 7
3 x a = 12
a = 12 : 3
a = 4 → numarul ,,initial"
Verific:
[ ( 3 x 4 + 7 ) x 8 - 7 ] : 5 = ( 19 x 8 - 7 ) : 5 = ( 152 - 7 ) : 5 = 145 : 5 = 29
[ ( 3 × a + 7 ) × 8 - 7 ] : 5 = 29
[ ( 3a + 7 ) × 8 - 7 ] = 29 × 5
[ ( 3a + 7 ) × 8 - 7 ] = 145
[ ( 3a + 7 ) × 8 ] - 7 = 145
( 3a + 7 ) × 8 = 145 + 7
( 3a + 7 ) × 8 = 152
3a + 7 = 152 : 8
3a + 7 = 19
3a = 19 - 7
3a = 12
a = 12 : 3
a = 4 → numarul cautat
❤❤❤ Succes ❤❤❤