What is the value of (27x3 + 58x2y + 31xy2 + 8y3), when x = 5 and y = -7?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. -1924.
27x3 + 58x2y + 31xy2 + 8y3
⇒ 27x3 + 8y3 + 54x2y + 36xy2 + 4x2y - 5xy2
⇒ (3x + 2y)3 + 4x2y - 5xy2
Put x = 5, y = -7
⇒ (15 - 14)3 + 4 × 52 × (-7) - 5 × 5 × (-7)2
⇒ 1 - 700 - 1225
⇒ -1924