Answer:
a-b = 31 (a ≠ b)
Step-by-step explanation:
(3x²-x+1)(px²+qx+1) = ax⁴+bx³+12x² - 6x + 1
3px⁴+(3q-p)x³+(3+p-q)x²+(q-1)x+1 = ax⁴+bx³+12x² - 6x + 1
q-1 = -6 q = -5
3+p-q = 3+p-(-5) = 8+p = 12 p = 4
b = 3q-p = 3*(-5) - 4 = -19
a = 3p = 3*4 = 12
a-b = 12 - (-19) = 31
