Answer:
z+7
Step-by-step explanation:
Firstly once you see the word sum it means you will have to add up to get a specific number
For example the sum of 6 and 7 means 6+7 which will give us 13
The sum of z and 7 will z+7,but we observe that z is not a number so we cannot add z+7 but in the case of multiplication that is z×7
It will give us 7z but the case of addition is totally different from that of multiplication
Therefore the final answer is z+7
