`2/3 + 1 5/7 : x = 7/5`

`=> 2/3 + 12/7 : x = 7/5`

`=> 12/7 : x = 7/5 - 2/3`

`=> 12/7 : x = 11/15`

`=> x = 12/7 : 11/15`

`=> x = 180/77`

`S = (7,2)/80 . 100 = 9 ( g )`

`mdd = 7,2 + 80 = 87,2 ( g )`

`C % = (7,2)/(87,2) . 100 = 8,26%`

`( 2 4/5 + 1/5 - x ) xx 7/5 = 2 1/10`

`=> ( 14/5 + 1/5 - x ) xx 7/5 = 21/10`

`=> ( 3 - x ) xx 7/5 = 21/10`

`=> 3 - x = 21/10 : 7/5`

`=> 3 - x = 3/2`

`=> x = 3 - 3/2`

`=> x = 6/2 - 3/2`

`=> x = 3/2`

`268`

Số đó là : `(235 + 700) : 5 = 187`

`3/8 + 2 5/8 xx x = 5/4`

`2 5/8 xx x = 5/4 - 3/8`

`21/8 xx x = 7/8`

`x = 7/8 : 21/8`

`x = 7/8 xxx 8/21`

`x = 7/21`

`x = 1/3`

`color{pink}{#Fensiyagi}`