Answer:
So, first you would need to multiply 6 by $35.50, then take that number and add it to the $420 to get $633.00. Then you need to multiply $310.75 by 4. After take that $1243.00 and subtract $633.00 from it to get $610.00.
the answer is: Diego would need to add at least $610 to his account to cover his checks.
Explaination: