a, 6x = 613 + 5
6x = 618
x = 618 : 6
x = 103
b,x - 47 = 115
x = 115 + 47
x = 162
c,146 - x = 401 - 315 = 86
x = 146 - 86
x = 60
d,6x + 70 = 575 - 445 = 130
6x = 130 - 70 = 60
x = 60 : 6
x = 10
e, x - 5 = 15
x = 15 + 5
x = 20
f,x - 105 = 15 . 21 = 315
x = 315 + 105
x = 420
a) 6x-5=613
=> 6x = 613-5
=> 6x= 618
=> x= 618 : 6 = 103
vậy x =103
b) (x-47)-115=0
=> (x-47)= 0+115=115
=> x-47=115
=> x = 115 + 47 = 162
vậy x=162
c) 315+(146-x)=401
=> (146-x)=401-315
=> (146-x)= 86
=> 146-x=86
=> x= 146-86
=> x= 60
vậy x=60
d) 575-(6x +70) =445
=> (6x+70)= 575-445
=>6x+70= 130
=>6x=130-70
=>6x= 60
=>x= 60:6
=> x=10
vậy x=10
e) x-105 : 21 =15
=>x- (105:21) =15
=>x- 5=15
=>x=15+5
=>x=20
vậy x= 20
f) (x-105):21=15
=> (x-105) = 15.21
=>x-105= 315
=>x= 315+105
=>x= 420
vậy x=420
