What are the factors of 3x2 + 13x + 4?

Step-1 : Multiply the coefficient of the first term by the constant   3 • 4 = 12 

Step-2 : Find two factors of  12  whose sum equals the coefficient of the middle term, which is   13 .


-12   +   -1   =   -13     
-6   +   -2   =   -8     
-4   +   -3   =   -7     
-3   +   -4   =   -7     
-2   +   -6   =   -8     
-1   +   -12   = -13     
1   +   12   =   13