How do I find the original equation or derivative?

Question

Find f. (Use C for the constant of the first antiderivative and D for the constant of the second antiderivative.)

f ''(x) = 28x³ − 18x² + 8x

Answer 1

f'(x) = 7x⁴ - 6x³ + 4x² + C

f(x) = (7/5)x⁵ - (3/2)x⁴ + (4/3)x³ + (C)x+ D