1. The absolute value function takes any quantity and makes it positive, so it's impossible to have |3x + 7| < 0. There is no solution.
2. If b + 5 ≥ 0, then
|b + 5| = b + 5 = 2b - 9
b = 14
Otherwise, if b + 5 < 0, then
|b + 5| = -(b + 5) = 2b - 9
-b - 5 = 2b - 9
3b = -4
b = -4/3
However, this second solution is extraneous, since the left side is positive,
|-4/3 + 5| > 0
while the right side is negative,
2•(-4/3) - 9 = -8/3 - 9 < 0