What is the twice of constant term in (5x2-\(\frac{1}{x}\))3
Answer & explanation
Correct answer: option 3
(5x2-\(\frac{1}{x}\))3 = (5x2)3 - (\(\frac{1}{x}\))3 - 3×5x2×\(\frac{1}{x}\)(5x2-\(\frac{1}{x}\))
⇒........ -(3 × 5x × 5x2) + (3 × 5x × \(\frac{1}{x}\))
⇒........ -75x3 + 15
15 is the constant term
So, 15 × 2 = 30