Answer:
7x - 2
Explanation:
let x be the number of bags of chips, then
3x is the number of bags of pretzels ← 3 times the number of bags of chips
3x - 2 is the number of bags of nachos ← 2 less than bags of pretzels
total snacks bought = x + 3x + 3x - 2 = 7x - 2