Answer:
a) a = 5, b = 3.
Step-by-step explanation:
We use the Remainder theorem here:
Lets try a = 5 and b = 3 and when x + 2 is the divisor then P(-2) will be -10:
P(x) = 6x^3 + 5x^2 - 3x + 12
p(-2) = 6(-2)^3 + 5(-2)^2 -3(-2) + 12
= -48 + 20 + 6 + 12
= -48 + 38
= -10.
Also using x + 1 we find that p(-1) = 14 so this is the answer.