Find the errors and correct the following mathematical sentence:(2a +

1.	Find the errors and correct the following mathematical sentence:(2a + 3)2 = 2a2 + 6a +9
Answer» (2a + 3)² = 2a² + 6a +9 ⇒ (2a)² + 2 × 2a × 3 + 3² = 2a² + 6a + 9 ⇒ 4a² + 12a + 9 = 2a²+ 6a + 9 ⇒ 4a² – 2a² = 6a – 12a ⇒ 2a² = – 6a ⇒ 2a ≠ 6 ∴ The given sentence is wrong. Correct sentence is (2a + 3)² = 4a² + 12a + 9.

Find the errors and correct the following mathematical sentence:(2a + 3)2 = 2a2 + 6a +9

Answer»

(2a + 3)² = 2a² + 6a +9

⇒ (2a)² + 2 × 2a × 3 + 3² = 2a² + 6a + 9

⇒ 4a² + 12a + 9 = 2a²+ 6a + 9

⇒ 4a² – 2a² = 6a – 12a

⇒ 2a² = – 6a

⇒ 2a ≠ 6

∴ The given sentence is wrong.

Correct sentence is (2a + 3)² = 4a² + 12a + 9.