The concentration C C\,C of a specific reagent in a chemical solution depends on the temperature fluctuation τ\tauτ (in degrees Celsius). For small fluctuations near a reference point, the relationship is modeled by the function:
C(τ)=(5−25τ)7C(\tau) = \left(5 - \frac{2}{5}\tau\right)^7C(τ)=(5−52τ)7
Find the first four terms, in ascending powers of τ\tauτ, of the binomial expansion of C(τ)C(\tau)C(τ). Give each coefficient as an integer.