Answer:
x=3
Explanation:
The equation will be 3+6x=21 since we know that the soft drink costs 3 dollars and he bought 6 candy bars(6 times x or 6x). We also know that the total cost for this merchandise is 21 dollars. Now you solve the equation! First subtract 3 from both sides(since the inverse for addition is subtraction we SUBTRACT 3 from bothe sides). You are left with 6x=21-3 or 6x=18. Now you divide Each side by 6(because the inverse operation of multiplication is division). You have the answer! x=18/6 or x=3! Hope it helped!!