Question

Describe the error in finding the product
A The 16 should be 8.

B The k2 should be 2k.

C The middle term, (k)(4), is missing.

D The middle term, 2(k)(4), is missing.

The product is what

Answer 1

The error is D. The middle term 2(k)(4) is missing.

Explanation:

• We have the mathematical formula - (A + B)² = A² + B² + 2× A× B.

• To solve for (k + 4)², we take k as the A term and 4 as the B term. So we must calculate the values of A², B² and 2× A× B.
• If A = k, A² = k²,                                                                                                                    B = 4, B² = 4² = 16,                                                                                                           2× A× B = 2× k× 4 = 8 × k = 8k.
• So (k + 4)² = k² + 16 + 8k. In the image it is given that (k + 4)² = k² + 16 but in this the middle term 2AB = 2(k)(4) = 8k is missing.