2|x + 1| + 1 < 19
1 is adding on the left, then it will subtract on the right
2|x + 1| < 19 - 1
2|x + 1| < 18
2 is multiplying on the left, then it will divide on the right
|x + 1| < 18/2
|x + 1| < 9
Now, we have two options:
x + 1 < 9 or x + 1 > -9
x < 9 - 1 x > -9 - 1
x < 8 x > -10
Then, the solution is -10 < x < 8