Răspuns :
ăm mie mi a dat asa..poate am greșit undeva sau poate ceva nu e bine cu enunțul

[ ( a × 2 + 79 ) × 3 - 120 ] : 5 = 121
( a × 2 + 79 ) × 3 - 120 = 121 × 5
( a × 2 + 79 ) × 3 - 120 = 605
( a × 2 + 79 ) × 3 = 605 + 120
( a × 2 + 79 ) × 3 = 725
a × 2 + 79 = 725 : 3
a × 2 + 79 = 241,66
a × 2 = 241,66 - 79
a × 2 = 162,66
a = 162,66 : 2
a = 81,33
( a × 2 + 79 ) × 3 - 120 = 121 × 5
( a × 2 + 79 ) × 3 - 120 = 605
( a × 2 + 79 ) × 3 = 605 + 120
( a × 2 + 79 ) × 3 = 725
a × 2 + 79 = 725 : 3
a × 2 + 79 = 241,66
a × 2 = 241,66 - 79
a × 2 = 162,66
a = 162,66 : 2
a = 81,33