a) (158-x):7=20`
`=> 158-x=20 . 7`
`=> 158-x=140`
`=> x=158-140`
`=> x=18`
Vậy `x = 18`
`b)5x+35=330`
`=> 5x=330-35`
`=> 5x=295`
`=> x=295:5`
`=> x=59`
Vậy `x=59`
(158-x):7=20
158-x=20x7
158-x=140
x=158-140
x=18
Vậy x=18
b,5.x+35=330
5.x=330-35
5.x=295
x=295:5
x=59
Vậy x=59
\(a,\left(158-x\right)=20\times7\)
\(158-x=140\)
\(x=158-140\)
\(x=14\)
\(b,5.x+35=330\)
\(5.x=330-35\)
\(5.x=295\)
\(x=295:5\)
\(x=59\)