I'm sorry I would help but I'm going to have to say b sorry for not being able to show
Answer:

Step-by-step explanation:
Given




Required
Evaluate 
Expand

Further expand

Apply product rule of logarithm

Substitute values for log(7) and log(3)


Answer:
a) 5.6
Step-by-step explanation:
sin 22° = x/15
0.3746 = x/15
x = 5.62