Answer:
a = 4, b = - 5, c = 5
Step-by-step explanation:
Expand the product of factors on the left side and compare like terms on both sides.
(3x - 1)(ax + b) ← expand using FOIL
= 3ax² + 3bx - ax - b
= 3ax² + (3b - a)x - b
Equating coefficients of like terms with 12x² - 19x + c , then
3a = 12 ( divide both sides by 3 )
a = 4
3b - a = - 19
3b - 4 = - 19 ( add 4 to both sides )
3b = - 15 ( divide both sides by 3 )
b = - 5
c = - b = - ( - 5) = 5
