This video explains what the parameters a, k, d, and c do to transform the function f(x) for function g(x) = af[k(x-d)]+c.
a > 1 or a < -1; vertical stretch
-1 < a < 1; vertical compression
a < 0; vertical reflection
k > 1 or k < -1; horizontal compression by 1/k
-1 < k < 1; horizontal stretch by 1/k
k < 0; horizontal reflection
d > 0; shift right
d < 0; shift left
c < 0; shift down
c > 0; shift up