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

### Instruction:
 一个农场的母鸡数量是公鸡数量的9倍减去5只。如果总共有75只鸡，那么有多少只母鸡？


### Response:
 让x代表公鸡的数量
母鸡的数量：9x-5
总数：9x-5+x=75
10x-5=75
10x=80
x=<<8=8>>8
母鸡的数量：9(8)-5=67