RRB NTPC · Question 63
If (a + c + 1) = 0, then find the value of (a^3 + c^3 + 1 – 3ac)
Show answer & explanation
Answer: (D) 0
Explanation
Use the identity x³ + y³ + z³ − 3xyz = (x + y + z)(x² + y² + z² − xy − yz − zx). With x = a, y = c and z = 1, the expression a³ + c³ + 1 − 3ac has the factor a + c + 1, which is 0. So the value is 0.