1.Tìm x biết: 2 và 1/2 -x+4/5=2/3-(-4/7) 1 và 4/5=-0,15-x -4/7-x=3/5-2x (3/8-1/5)+(5/8-x)=1/5 2.Q=9-|x-1/10|

`a)` `2(1)/(2)-x+4/5=2/3-(-4/7)`

`⇔5/2-x+4/5=2/3+4/7`

`⇔5/2+4/5-x=14/21+12/21`

`⇔25/10+8/10-x=26/21`

`⇔33/10-x=26/21`

`⇔x=33/10-26/21`

`⇔x=693/210-260/210`

`⇔x=433/210`

`b)` `1(4)/(5)=-0,15-x`

`⇔9/5=-3/20-x`

`⇔9/5+(-3/20)=x`

`⇔x=-3/20-9/5`

`⇔x=-39/20`

`c)` `-4/7-x=3/5-2x`

`⇔-x+2x=3/5+4/7`

`⇔x=41/35`

`d)` `(3/8-1/5)+(5/8-x)=1/5`

`⇔3/8-1/5+5/8-x=1/5`

`⇔3/8+5/8-1/5-x=1/5`

`⇔1-1/5-x=1/5`

`⇔4/5-x=1/5`

`⇔x=4/5-1/5=3/5`