Answer:
(a) Loss from selling 15 necklaces
(b)

Explanation:
The question has missing details. (See the comment section for missing details)
Given

Solving (a): Will she make a profit from 15 necklaces
To do this, we substitute 15 for b in



The inequality is not true.
Hence, she'll make a loss from selling 15 necklaces
Solving (b): An expression that represents profit.
To do this, we solve for b in

Collect Like Terms


Make b the subject


This implies that to make a profit, she must sell more than 18 necklaces.