a problem i have trouble with

Let 𝑓(𝑥)=⌊𝑥⌊𝑥⌋⌋f(x)=⌊x⌊x⌋⌋ for 𝑥≥0.

 

(a) Find all 𝑥≥0x≥0 such that 𝑓(𝑥)=1.f(x)=1.
(b) Find all 𝑥≥0x≥0 such that 𝑓(𝑥)=3.f(x)=3.
(c) Find all 𝑥≥0x≥0 such that 𝑓(𝑥)=5.f(x)=5.
(d) Find the number of possible values of 𝑓(𝑥)f(x) for 0≤𝑥≤10.

Thanks so much!