12, 2, 5, 4, 7
The coefficients are the numbers that are in front of the letters
4 x³ - 8 x² - 12 x =
= 4 x ( x² - 2 x - 3 ) =
= 4 x ( x² - 3 x + x - 3 ) =
= 4 x ( x ( x - 3 ) + ( x - 3 ) ) =
= 4 x ( x - 3 ) ( x + 1 ) ( the factored form )
#1) x-8= -12
#2) 15+k= 2
#3) x/-7= -20
#4) (5/8)(x)= -20
The / in #2 means to divide and the ( ) mean to multiply