1) |3k + 4| = 8?
2) |3x + 8| = 19?
3) |7x + 1|

Question

1) |3k + 4| = 8?
2) |3x + 8| = 19?
3) |7x + 1| < 13?
4) |3k + 4| = 8?
5) |7x + 1| < 13?

alfie · Answer

There you have the first equality, you can solve the other two by using the very same method. 
Regarding the inequalities, you will have to make a graph and find the solutions.

turingtest · Answer

I will solve the first for you, you should be able to do the rest (they are all done the same way)$$\left| 3k+4 \right|=19$$means that either

3k+4=19       or       3k+4=-19
     3k=15       or            3k=-23
       k=5         or              k=-23/3
so k={-23/3,5}

anonymous · Answer

If |x| = +x if x >0
        = -x if x < 0