Rezolvare:
(a × 2) × 4 = 40
a × 2 = 40 : 4
a × 2 = 10
a = 10 : 2
[tex]\boldsymbol{ \red{ a = 5}}[/tex]
***
a - 10×5 = 150
a - 50 = 150
a = 150 + 50
[tex]\boldsymbol{ \red{a = 200}}[/tex]
***
181 - a × 9 = 100
a × 9 = 181 - 100
a × 9 = 81
a = 81 : 9
[tex]\boldsymbol{ \red{ a = 9}}[/tex]