Answer:
a. 12s + 19j - 3
36 + 28 - 3 = 61
b.
Shirt (per unit cost):
Before Discount: $12
After Discount: $12 - $3 = $9
Jeans (pair cost):
Before Discount: $19
After Discount: $19 - $3 = $16
(12-3)s + (19-3)j
27 + 32 = $59
first off let's convert the mixed fractions to improper fractions.

she already did half a hat, so we can say 
so she only needs enough fabric to make 3 more full hats, we know each one uses 9/7 ft, so
