`#Aridoto`

Bài `2:`

`1.`

`6a<= 6b`

`<=>(6a)/6<=(6b)/6`

`<=>a<=b`

`2.`

`3a+1>= 3b+1`

`<=>3a>=3b`

`<=>(3a)/3>=(3b)/3`

`<=>a>=b`

`3.`

`5a-1>5b-1`

`<=>5a>5b`

`<=>(5a)/5>(5b)/5`

`<=>a>b`

`4.`

`8-a<8-b`

`<=>-a<-b`

`<=>(-a)/(-1)>(-b)/(-1)`

`<=>a>b`

`5.`

`-3a>= -3b`

`<=>(-3a)/(-3)<=(-3b)/(-3)`

`<=>a<b`

`6.`

`-2a+3>=3-2b`

`<=> -2a>= -2b`

`<=>(-2a)/(-2)<=(-2b)/(-2)`

`<=>a<=b`

--------------------------------------------

Bài `3:`

Với `a<b`

`1. 2a+1<2b+2`

`a<b`

`=>2a<2b`

`=>2a+1<2b+2`

`2. ` `-2a-5>-2b-7`

`a<b`

`=>2a<2b`

`=>2a+5<2b+7`

`=> -(2a+5)> -(2b+7)`

`=> -2a-5 > -2b-7`

`3.` `4a+2<4b+3`

`a<b`

`=>4a<4b`

`=>4a+2<4b+3`