Simplify the following expression: 25 × 25 + 9 × 9 + 6 × 6 + 2 × 25 × 9 + 2 × 9 × 6 + 2 × 25 × 6
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 1600.
25 × 25 + 9 × 9 + 6 × 6 + 2 × 25 × 9 + 2 × 9 × 6 + 2 × 25 × 6
a2 + b2 + c2 + 2ab + 2bc + 2ac = (a + b + c)2
⇒ 252 + 92 + 62 + 2 × 25 × 9 + 2 × 9 × 6 + 2 × 25 × 6 = (25 + 9 + 6)2 = (40)2 = 1600