Question

If p(x) = 2x³ + ax² − 7x + b and we want p(1) = 3 and p(2) = 19 what should be a and b?

Answer 1

Putting the value of b from equation (1):

⇒ 4a + (8 − a) = 17

⇒ 3a + 8 = 17

⇒ 3a = 17 − 8

⇒ 3a = 9

Putting the value of a in equation (1):

b = 8 − 3 = 5

Thus, the values of a and b are 3 and 5 respectively.