Here are the equations based on the sentences in the image, using $n$ as the unknown number:

i. A certain number is multiplied by 8, then 11 is added, and the result is 39: $8n + 11 = 39$

ii. I think of a number, double it, add 7, and the result is 5: $2n + 7 = 5$

iii. I think of a number, add 4, and then divide the result by 10. The answer is 7: $\frac{n + 4}{10} = 7$

Would you like me to solve these equations or provide more details?

Here are some related questions for further practice:

1. How do you solve the equation $8n + 11 = 39$?
2. What steps are needed to isolate $n$ in $2n + 7 = 5$?
3. How do you handle fractions in an equation like $\frac{n + 4}{10} = 7$?
4. What happens if the number in equation (ii) is tripled instead of doubled?
5. How can you check if your solutions are correct after solving?

Tip: Always reverse the operations in the correct order when solving equations to isolate the variable.