Question

*Expand the given equation: (k + 7)³*

1️⃣ k³ + 21k² + 147k + 343
2️⃣ k³ + 3k² + 14k + 343
3️⃣ k³ + 343
4️⃣ None of these​

Answer 1

Answer:

none of these

(a+b)^3= a^3+b^3+3a^2b+3ab^2

Answer 2

Answer:

(1) k³ + 21k² + 147k + 343

Step-by-step explanation:

(a + b)³ = a³ + 3a²b + 3ab² + b³

(k + 7)³ = k³ +  7³ + 3 × k × 7(k + 7)

(k + 7)³ = k³ +  7³ + 21k(k + 7)

            = k³ + 7³ + 21k² + 147k

            = k³ + 21k² + 147k + 343

Hope it helps :D