Simplifying
f(x) = 6x5 + 5x4 + 4x
Multiply f * x
fx = 6x5 + 5x4 + 4x
Reorder the terms:
fx = 4x + 5x4 + 6x5
Solving
fx = 4x + 5x4 + 6x5
Solving for variable 'f'.
Move all terms containing f to the left, all other terms to the right.
Divide each side by 'x'.
f = 4 + 5x3 + 6x4
Simplifying
f = 4 + 5x3 + 6x4