Replace x with -4 so it would be:
f(-4)= 2(-4)=-8
-8 is your answer
The number of the product is 9
-2x < = 3x + 1 < = 10
split them
-2x < = 3x + 1 3x + 1 < = 10
-2x - 3x < = 1 3x < = 10 - 1
-5x < = 1 3x < = 9
x > = -1/5 x < = 3
solution is : -1/5 < = x < = 3 <==
D is the correct answer to this question.