What is the constant term in the expansion of ≤ft(5 x^2-1/x)^3 ?

(a - b)³ = a³ - b³ - 3ab(a-b)

$\left(5 x^2-\frac{1}{x}\right)^3$ = (5x²)³ - \(\frac{1}{x^3}\) - 3 × 5x × \(\frac{1}{x}\)($\left(5 x^2-\frac{1}{x}\right)$

$\left(5 x^2-\frac{1}{x}\right)^3$ = 125x⁶ – \(\frac{1}{x^3}\) – 75x³ + 15

So the constant term will be = 15