Question

If the value of the polynomial m³ + 2m + a is 12 for m = 2,  then find the value of a.

Answer 1

Let  p(m) = m³ + 2m + a

For m = 2, p(2) = 12

∴ (2)³ + 2 × 2 + a = 12

⇒ 8 + 4 + a = 12

⇒ 12 + a = 12

⇒ a = 12 - 12 = 0

Thus, the value of a is 0.