a,123-5(x+4)=28
(=)5(x+4)=85
(=) x+4=17
(=) x=13
b,10+2x=2.\(\left(3^2-1\right)\)
(=) 10+2x=16
(=) 2x = 6
(=)x=3
A, 123-5.(x+4)=38
5.(x+4)=123-38
5.(x+4) =85
(x+4)=85:5
(x+4)=17
x =17-4
x =13
B, 10+2x=2(\(3^2-1\))
10+2x=2.8
10+2x=16
2x=16-10
2x=6
x=6:2
x =3
a, 123 - 5(x + 4) = 38
=>5(x + 4) = 85
=> x + 4 = 17
=> x = 13
vậy_
10 + 2x = 2(32 - 1)
=> 10 + 2x = 2.8
=> 10 + 2x = 16
=> 2x = 6
=> x = 3
vậy_
Bài 1 :Tìm x :
A , 123 - 5 . ( x + 4 ) = 38
<=> 5 . ( x + 4 ) = 123 - 38
<=> 5 . ( x + 4 ) = 85
<=> x + 4 = 85 : 5
<=> x + 4 = 17
<=> x = 17 - 4
<=> x = 13
Vậy x = 13
B, 10 + 2x = 2 . ( 32 - 1 )
<=> 10 + 2x = 2 . ( 9 - 1 )
<=> 10 + 2x = 2 . 8
<=> 10 + 2x = 16
<=> 2x = 16 - 10
<=> 2x = 6
<=> x = 6 : 2
<=> x = 3
Vậy x = 3