Answer:
The solutions for 3 questions are explained one after the other below.
Step-by-step explanation:
1).Let x be the number of paperback books that she buys, y be the number of hardback books that she buys.
for the first condition, i.e, she has decided to spend at most $150.00 on books,the required inequality will be :

for the second condition , i.e, she wants to purchase at least 12 books,
the required inequality will be:

2). the graph is in the attachment..
3). x,y are the two required solutions. where,
x =number of paperback books she buys.
y=number of hardback books she buys.