\(1,x:2+x:3+x:6=12\\x\times\dfrac{1}{2}+x\times\dfrac{1}{3}+x\times\dfrac{1}{6}=12\\ x\times\left(\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{6}\right)=12\\ x\times\left(\dfrac{3}{6}+\dfrac{2}{6}+\dfrac{1}{6}\right)=12\\ x\times1=12\\ x=12:1\\ x=12 \)
\(2,\left[35-\left(x+3\right)\right]\times17=34\\ 35-\left(x+3\right)=34:17\\ 35-\left(x+3\right)=2\\ x+3=35-2\\ x+3=33\\ x=33-3\\ x=30\)
\(3,15-2\times\left[13-\left(x+8\right)\right]=26:2\\ 15-2\times\left[13-\left(x+8\right)\right]=13\\ 2\times\left[13-\left(x+8\right)\right]=15-13=2\\ 13-\left(x+8\right)=2:2\\ 13-\left(x+8\right)=1\\ x+8=13-1\\ x+8=12\\ x=12-8\\ x=4\)
\(4,100+2\times\left(3-x\right)-45:9=99\\ 100+2\times\left(3-x\right)-5=99\\ 100+2\times\left(3-x\right)=99+5\\ 100+2\times\left(3-x\right)=104\\ 2\times\left(3-x\right)=104-100=4\\ 3-x=4:2\\ 3-x=2\\ x=3-2\\ x=1\)
`5,(x+1) xx8 +(x+1) xx 3+x+1=24`
`(x+1) xx ( 8 + 3 + 1)=24`
`(x+1) xx 12=24`
`x+1=24:12`
`x+1=2`
`x=2-1`
`x=1`
`#` `QAnhh`
1: =>x*1=12
=>x=12
2: =>35-(x+3)=2
=>x+3=33
=>x=30
3: =>2[5-x]=15-13=2
=>5-x=1
=>x=4
4 và 5
