Tìm x biết: a) (x-14)-20=0 b) 25-(2.x+10)=5 c) 315-(315-x)=215 d) 128+(202-x)=330 e) x -320:32=25.16 f) (x-120).9=450

Đáp án + Giải thích các bước giải:

` a) (x-14)-20=0 `

` =>x-14=0+20 `

` =>x-14=20 `

` =>x=20+14 `

` =>x=34 `

Vậy ` x=34 `

` b) 25-(2x+10)=5 `

` =>2x+10=25-5 `

` =>2x+10=20 `

` =>2x=20-10 `

` =>2x=10 `

` =>x=10:2 `

` =>x=5 `

Vậy ` x=5 `

` c) 315-(315-x)=215 `

` =>315-x=315-215 `

` =>315-x=100 `

` =>x=315-100 `

` =>x=215 `

Vậy ` x=215 `

` d) 128+(202-x)=330 `

` =>202-x=330-128 `

` =>202-x=202 `

` =>x=202-202 `

` =>x=0 `

Vậy ` x=0 `

` e) x-320:32=25.16 `

` =>x-10=400 `

` =>x=400+10 `

` =>x=410 `

Vậy ` x=410 `

` f) (x-120).9=450 `

` =>x-120=450:9 `

` =>x-120=50 `

` =>x=50+120 `

` =>x=170 `

Vậy ` x=170 `

` #owen `