Question

In a polynomial P(x) = 2x³ + 9x² + kx + 3, P(-2) = P(-3) . Find the value of k

• A. 8
• B. 5
• C. 7
• D. 10

Answer 1

Answer:

C. 7

P(x) = 2x³ + 9x² + kx + 3, P(-2) = P(-3) P(-2) = 2(-2)³ + 9(-2)² + k(-2) + 3 = -16 + 36 -2k + 3 = 23 - 2k P(-3) = 2(-3)³ + 9(-3)² + k(-3) + 3 = -54 + 81 -3k + 3 = 30 - 3k Since P(-2) =P(-3) 23 - 2k = 30 - 3k k = 7