Due to BD is an angle bisector, you have that ∠ADB and ∠DBC are equal.
Then, you have:
7).
m∠ADB = m∠DBC replace by the expressions given in the figure
54 = x - 29 add 29 both sides
54 + 29 = x
83 = x
x = 83
Hence, x is x = 83
9).
3x + 4 = 25 subtract 4 both sides
3x = 25 - 4
3x = 21 divide by 3 both sides
x = 21/3
x = 7
Hence, x is x = 7