Example 1easy
- A)Ravi used the identity (a - b)² instead of (a + b)².
- B)Ravi squared the constant terms incorrectly; 3² should be 6 and 2² should be 4.
- C)Ravi forgot to include the middle term, 2ab, from the identity (a + b)².
- D)Ravi incorrectly identified 'a' as 3x and 'b' as 2y.
Step-by-step solution
- The correct algebraic identity for (a + b)² is a² + 2ab + b².
- In the expression (3x + 2y)², 'a' is 3x and 'b' is 2y.
- So, (3x + 2y)² = (3x)² + 2(3x)(2y) + (2y)² = 9x² + 12xy + 4y².
- Ravi's expansion 9x² + 4y² only includes the a² and b² terms, missing the 2ab term (which is 12xy).
Answer: Ravi forgot to include the middle term, 2ab, from the identity (a + b)².