|a-1|=3

|2a+5|>3

3|a-6|+12

1st one, in your head,

a = 4 or a = -2

2. |2a+5| > 3
2a+5 > 3 OR -2a -5> 3
a > -2 OR a < -4

3. looks like a typo , I see neither an equation nor an in-equation.
If it is one of those, first divide both sides by 3, then it is very easy.