E.467. Aflați valoarea numărului aaa din egalitatea: 1800−[150+(50×3+50×a)]=800.1800-[150+(50 \times 3 + 50 \times a)] = 800.1800−[150+(50×3+50×a)]=800.
14.14.14.
1800−800−[150+(50×3+50×a)]=0.1800-800 - [150+(50 \times 3 + 50 \times a)] = 0.1800−800−[150+(50×3+50×a)]=0. 1000−[150+(150+50×a)]=0.1000 - [150+(150 + 50 \times a)] = 0.1000−[150+(150+50×a)]=0. 150+(150+50×a)=1000.150 + (150 + 50 \times a) = 1000.150+(150+50×a)=1000. 150+50×a=850150 + 50 \times a = 850150+50×a=850 50×a=700⇒a=14.50 \times a = 700 \Rightarrow \boxed{a=14}.50×a=700⇒a=14.