Below is an instruction that describes a task. Write a response that appropriately completes the request in Thai. Please answer in Thai.

### Instruction:
John's pool is 5 feet deeper than 2 times Sarah’s pool. If John’s pool is 15 feet deep, how deep is Sarah’s pool?

### Response:
 กำหนดให้ x เป็นจำนวนฟุตของสระว่ายน้ำของจอห์น
2*x + 5=15
2x=10
x=5