Y= ∛(-x) - 3
for x = -8 → y = ∛-(-8) - 3 ↔ y = 2-3 ↔y = -1
for x= 8 → y= ∛(-8) - 3 ↔ y = -2 -3 ↔ y = -5
Then - 5≤ y≤ - 1
hence the range of y is {y|-5≤y≤-1}
The answer to the problem is x=7. Here is the work:
Total purchase she did : $20.90+$18.95=$39.85
7% tax means that we have to 7% or (7/100) extra
7% X 39.85= 2.79
total pay: 39.85+2.79=42.64
total cash: $50
what she gets back: 50-42.64=7.36