ANSWER
To get 3 bags of chips and 6 bottles of juice would cost $9.15
To get x bags of chips and y bottles of juice would cost 1.25x + 0.9y
Step-by-step explanation
Each bag of chip costs $1.25. So 3 bags of chips cost 3 times that:
Each bottle of juice costs $0.90, so 6 bottles of juice cost 6 times that:
The cost for all of these items is the sum of these costs: