a) (a-80) x2 -146=24
(a-80) x2=24+146
(a-80) x2=170:2
a-80=85
a=85+80
a=165
Verificare: (165-80)x2-146=85x2=146
b) (100-b:3)x5 =490
(100-b:3)=490:5
100-b:3=98
b:3=100-98
b:3=2x3
b=6
Verificare: (100-6:3)x5=(100-2)x5=98x5=490
c) (c:9:3)x4=20
c:9:3=20:4
c:9:3=5x3
c:9=15x9
c= 135
Verificare:(135:9:3)x4=(15:3)x4=5x4=20
Sper ca te-am ajutat!
