Cube of (a + 1) is = ………………… A) a2 + 1 B) a + 2a + 1

1.	Cube of (a + 1) is = ………………… A) a2 + 1 B) a + 2a + 1 C) a + 3a + 3 D) 3a – 3
Answer» C) a + 3a + 3 Correct option is (C) \(a^3+3a^2+3a+1\) \((a+1)^3\) \(=(a+1)^2(a+1)\) \(=(a^2+2a+1)(a+1)\) \(=a^3+2a^2+a+a^2+2a+1\) \(=a^3+3a^2+3a+1\)

Cube of (a + 1) is = ………………… A) a2 + 1 B) a + 2a + 1 C) a + 3a + 3 D) 3a – 3

Answer»

C) a + 3a + 3

Correct option is (C) \(a^3+3a^2+3a+1\)

\((a+1)^3\) \(=(a+1)^2(a+1)\)

\(=(a^2+2a+1)(a+1)\)

\(=a^3+2a^2+a+a^2+2a+1\)

\(=a^3+3a^2+3a+1\)