Tìm x: a,x- 3/7=7/8 b,-2/3x + 1/5=1/10 c,1/3+2/3: x=-7 d,(4,5-2x) .1 4/7=11/14 e,2.(1/2x - 3/2=1/4 f,( x-4/5).(x+2 1/5)=0 g, x+ 3,12 = 14,6 -8,5 h,x-5,14=(15,7+2,3).2 i,x : 2,2=(18,6-12,3):3

`a,x- 3/7=7/8`

 `<=>x=7/8+3/7`

`=>x=73/56`

`b,-2/3x + 1/5=1/10`

`<=>-2/3x=1/10-1/5`

`<=>-2/3x=-1/10`

`<=>x=-1/10÷(-2)/3`

`=>x=3/20`

`c,1/3+2/3÷ x=-7`

`<=>2/3÷x=-7-1/3=-22/3`

`<=>x=2/3÷(-22)/3`

`=>x=1/11`

`d,(4,5-2x) *14/7=11/14`

`<=>4,5-2x=11/14÷14/7=11/28`

`<=>2x=4,5-11/28=115/28`

`<=>x=115/28÷2`

`=>x=115/56`

`e,2.(1/2x - 3/2)=1/4`

`<=>1/2x-3/2=1/4÷2=1/8`

`<=>1/2x=1/8+3/2=13/8`

`=>x=13/8÷1/2`

`=>x=13/4`

`f,( x-4/5).(x+2 1/5)=0`

$\left \{ {{x-\frac{4}{5} =0} \atop {x=\frac{21}{5} =0}} \right.$

$\left \{ {{x=\frac{4}{5} } \atop {x=\frac{-21}{5}}} \right.$

`=>x∈{4/5;(-21)/5}`

`g, x+ 3,12 = 14,6 -8,5`

`=>x=14,6-8,5-3,12`

`=>x=2,98`

`h,x-5,14=(15,7+2,3)*2`

`<=>x-5,14=18*2`

`<=>x-5,14=36`

`=>x=36+5,14`

`=>x=41,14`

`i,x ÷ 2,2=(18,6-12,3)÷3`

`<=>x÷2,2=6,3÷3`

`<=>x÷2,2=2,1`

`=>x=2,2*2,1`

`=>x=4,62`

____________Chúc bạn học tốt _____________

$#hodienquyen$