Answer:
a.
x+y=9 (1)
12x+16y=132 (2), where:
x is the number shirts
y is the number of pants
b. You bought 3 shirts and 6 pants.
Explanation:
The first equation would indicate that the number of shirts plus the number of pants is equal to 9:
x+y=9
The second equation would indicate that the price per shirt for the number of shirts plus the price per pant plus the number of pants is equal to 132:
12x+16y=132
The system of of linear equations that represents this situation is:
x+y=9 (1)
12x+16y=132 (2), where:
x is the number shirts
y is the number of pants
You can solve for x in (1):
x=9-y (3)
Then, you can replace (3) in (2):
12(9-y)+16y=132
108-12y+16y=132
4y=24
y=24/4
y=6
Now, you can replace the value of y in (3):
x=9-6
x=3