`493.`
`a)1/68 .[(3(10)/11-4):(21/22-1):(33/34-1)]`
`=1/68 .[(43/11-44/11):(21/22-22/22):(33/34-34/34)]`
`=1/68 .((-1)/11:(-1)/22:(-1)/34)`
`=1/68 . (-1)/11 . (-22)/1 . (-34)/1`
`=1`
`b)`Ta có:
`(0,8:(4/5 .1,25))/(0,64-1/25)=(4/5:(4/5 . 5/4))/(16/25-1/25)=(4/5:1)/(15/25)=(4/5)/(3/5)=4/5:3/5=4/5 . 5/3=4/3(1)`
Ta có:
`((1,08-2/25):4/7)/((6(5)/9-3(1)/4).2(2)/17)=((27/25-2/25):4/7)/((59/9-13/4). 36/17)=(1:4/7)/7=(7/4)/7=7/4 . 1/7=1/4`
`⇒(0,8:(4/5 .1,25))/(0,64-1/25):((1,08-2/25):4/7)/((6(5)/9-3(1)/4).2(2)/17)=4/3 . 1/4=1/3`
`c)(0,4+2/9-2/11)/(1,4+7/9-7/11):(1/3+0,25-1/5)/(1(1)/6+0,875-0,7)`
`=(2/5+2/9-2/11)/(7/5+7/9-7/11):(1/3+1/4-1/5)/(7/6+7/8-7/10)`
`=(2(1/5+1/9-1/11))/(7(1/5+1/9-1/11)):(2(1/6+1/8-1/10))/(7(1/6+1/8-1/10))`
`=2/7:2/7`
`=1`
`494.`
`a)(x+1/4-1/3).(2+1/6-1/4)=11/6`
`→(x+3/12-4/12).(24/12+2/12-3/12)=11/6`
`→(x-1/12). 23/12=11/6`
`→x-1/12=11/6:23/12`
`→x-1/12=11/6 . 12/23`
`→x-1/12=22/23`
`→x=22/23+1/12`
`→x=264/276+23/276`
`→x=287/276`
`b)2/3 .(1/2+3/4-1/3)≤x/18≤7/3 (1/2-1/6)`
`→2/3 .(6/12+9/12-4/12)≤x/18≤7/3 (3/6-1/6)`
`→2/3 . 11/12≤x/18≤7/3 . 2/6`
`→11/18≤x/18≤14/18`
`→11≤x≤14`
`→x∈{11;12;13;14}`
`c)18(373737/42424+373737/565656+373737/727272).x=-37`
`→18(37/42+37/56+37/72).x=-37`
`→37.18.(1/42+1/56+1/72).x=-37`
`→18.(1/(6.7)+1/(7.8)+1/(8.9)).x=(-37):37`
`→18(1/6-1/7+1/7-1/8+1/8-1/9).x=-1`
`→18(1/6-1/9).x=-1`
`→18(3/18-2/18).x=-1`
`→18. 1/18 .x=-1`
`→x=-1`
