if f(x)=5-2x+k, and f(f(k))=13, find the value of f(-4)?

f(x) = 5 - 2x + k

f(k) = 5 - 2k + k
Hence, f(k) = 5 - k

f(f(k)) = 13
5 - 2f(k) + k = 13
5 - 2(5 - k) + k = 13
5 - 10 + 2k + k = 13
3k = 18
k = 6

Hence, f(x) = 5 - 2x + 6
f(x) = 11 - 2x

f(-4) = 11 - 2(-4)
f(-4) = 19