a,70-5(x-3)=45
5(x-3) = 70 - 45
5(x-3) = 25
x-3 = 25 : 5
x - 3 = 5
x = 5 + 3
x = 8.
b,12+(5+x)=20
(5+x) = 20 - 12
(5+x) = 8
x = 8 - 5
x = 3
c,130-(100 + x)=25
100 + x = 130 - 25
100 + x = 105
x = 105 - 100
x = 5
Hok tốt !
a,70-5(x-3)=45
5(x-3) =70-45
5(x-3) =25
(x-3) =25:5
x-3 =5
x=5+3
x=8
a,70-5(x-3)=45
5(x-3)=70-45
5(x-3)=25
x-3=25:5
x-3=5
x=5+3
x=8
Vậy x=8
b,12+(5+x)=20
5+x=20-12
5+x=8
x=8-5
x=3
Vậy x=3
c,130-(100 + x)=25
100+x=130-25
100+x=105
x=105-100
x=5
Vậy x=5
5.(x-3) = 70-45
5.(x-3) =25
x-3 =5
x=5+3
x=8
b) 12+5+x=20
17+x=20 suy ra x=3
c) 100+x=130-25
100+x=105
x=105-100
x=5
a)70-5(x-3)=45
-5(x-3)=45-70
-5(x-3)=-25
x-3 =-25:-5
x-3=5
x=5+3
x=8
b)12+(5+x)=20
5+x=20-12
5+x =8
x =8-5
x =3
c)130-(100+x)=25
-(100+x )=25-130
100-x =-105
-x =-105-100
-x =-205
x =205
70-5.(x-3)=45
5.(x-3)=70-45
5.(x-3)=25
(x-3)=25:5
(x-3)=5
x =5+3
x =8