`1)c)` `2` phân số tối giản : `1/5 ; 12/35`
`2` phân số chưa tối giản : `2/6 ; 14/35`
__
`2)a) -3/8 + 1/4`
`= -3/8 + 2/8`
`= -1/8`
__
`b) 12/13 + (2021/2023 - 12/13)`
`=12/13 + 2021/2023 - 12/13`
`=(12/13-12/13)+2021/2023`
`=0+2021/2023`
`=2021/2023`
__
`c)5 3/7 - ( 2 2/9 - 5 3/7 )`
`=38/7 - (20/9 - 38/7)`
`=38/7 - 20/9 + 38/7`
`=76/7-20/9`
`=684/63-140/63`
`=544/63`
`=5 3/7 - 2 2/9 + 5 3/7`
__
`d)3 2/11 + 13/17 - (2 2/11 - 13/17 )`
`= 35/11 + 13/17 - ( 24/11 - 13/17 )`
`= 35/11 + 13/17 - 24/11 + 13/17`
`= 35/24 - 24/11 + 13/17 + 13/17`
`= 1 + 26/17`
`= 17/17 + 26/17`
`= 43/17`
__
`g)-7/2023 . 33/25 - 8/25 . 7/(-2023)`
`=-7/2023 . 33/25 - 8/25 .(-7/2023)`
`=-7/2023 . (33/25-8/25)`
`=-7/2023 . 25/25`
`=-7/2023 .1`
`=-7/2023`
__
`e)10/11-4/11:4-1/8`
`=10/11-4/11 . 1/4-1/8`
`=10/11-4/44-1/8`
`=10/11-1/11-1/8`
`=9/11-1/8`
`=72/88-11/88`
`=61/88`
__
`h)3/13-15/29+(-14/29)+10/13`
`=3/13-15/29-14/29+10/13`
`=(3/13+10/13)-(15/29-14/29)`
`=13/13-1/29`
`=1-1/29`
`=29/29-1/29`
`=28/29`
`3)a)x/8=9/12`
`=>12x=8.9`
`=>12x=72`
`=>x=72:12`
`=>x=6`
Vậy `x=6`
__
`b)10/19+3/19:x=1/2`
`=>3/19:x=1/2-10/19`
`=>3/19:x=19/38-20/38`
`=>3/19:x=-1/38`
`=>x=3/19:(-1/38)`
`=>x=3/19.(-38)`
`=>x=-114/19`
`=>x=-6`
Vậy `x=-6`
__
`c)12/17 - 3/17x = 12/17`
`=> 3/17x = 12/17 - 12/17`
`=> 3/17x = 0`
`=> x= 0 : 3/17`
`=> x =0`
Vậy `x=0`
__
`d)x-1/2x+1/5x=-26/5`
`=>1x-1/2x+1/5x=-26/5`
`=>2/2x-1/2x+1/5x=-26/5`
`=>1/2x+1/5x=-26/5`
`=>5/10x+2/10x=-26/5`
`=>7/10x=-26/5`
`=>x=-26/5:7/10`
`=>x=-26/5 . 10/7`
`=>x=-52/7`
Vậy `x=-52/7`
__
`l)(2x-4/3)-1 1/3 = -8/9`
`=>2x-4/3 = -8/9+4/3`
`=>2x-4/3= -8/9+12/3`
`=>2x-4/3=4/3`
`=>2x=4/3+4/3`
`=>2x=8/3`
`=>x=8/3:2`
`=>x=8/3 . 1/2`
`=>x=8/6`
`=>x=4/3`
Vậy `x=4/3`
__
`g)(x-1/5)(x+3/4)=0`
`=>x-1/5=0` hoặc `x+3/4=0`
`=>x=0+1/5` hoặc `x=0-3/4`
`=>x=1/5` hoặc `x=-3/4`
Vậy `x in{1/5;-3/4}`
