Question

64, –48, 36, –27, ...

Answer 1

The only formula that can be used to describe the sequence is definitely the third one $f(x + 1) = -3/4 f(x)$. So count like that$64* -\frac{3}{4} = -48 48* -\frac{3}{4} = 36$ and so on. You can check others by yourself to check if I'm right or not.