Heiii , nu stiu daca am fct corect dar sper ca este bine!
Răspuns:
[(2a + 3 )x4-5]:9 = 15| x9
(2a +3 )x4-5=135|+5
(2a+3)x4=140|:4
2a+3=10|-3
2a=7 |2
a=3,5
a:4:2:3+3x(96:4-21)=46|+21
a:4:2:3+3x24= 67
a:4:2:3 +72=67|-72
a;4:2:3=-5 |x3
a:4:2=-15|x2
a:4=-30|x4
a=-120
[(2a-56)x2-56] x2= 55|:2
(2a-56)x2-56= 27,5| + 56
(2a-56)x2=83,5|:2
2a-56=41,75|+56
2a=97,75|;2
a=48,875