`6x=613+5`
`6x=618`
`x=618:6`
`x=103`
_________________
`(x-47)-115=0`
`x-47=0+115`
`x-47=115`
`x=115+47`
`x=162`
_____________________
`315+(146-x)=401`
`146-x=401-315`
`146-x=86`
`x=146-86`
`x=60`
______________________
`575-(6x+70)=445`
`6x+70=575-445`
`6x+70=130`
`6x=130-70`
`6x=60`
`x=60:6`
`x=10`
____________________________
`x-105:21=15`
`x-5=15`
`x=15+5`
`x=20`
_______________________
`(x-105):21=15`
`x-105=15 xx 21`
`x-105=315`
`x=315+105`
`x=420`
a)
6.x-5=613
6.x=613+5
6.x=618
x=618:6=103
b) (x-47)-115=0
(x-47)=0+115
x-47=115
x=115+47=162.
c) 315+(146-x)=401
(146-x)=401-315
(146-x)= 86
x= 146-86=60.
d) 575-(6x+70)=445
(6x+70)=575-445
6x+70=130
6x=130-70
6x=60
suy ra x=0
e) x-105:21=15
x-5=15
x=15+5=20
f) (x-105):21=15
(x-105)=15x21
x-105=315
x=315+105
=420.
