So if you're adding two negatives you move left, positive you move right, and when you have to determine a negative, and a positive you just have to see which one is the farthest from zero which the farthest one's sign is either positive, or negative. Positive to move right, and negative to move left.
D. f(x+1)=2f(x)
f(x+1)=2(-2 2/3)=-5 1/3
f(x+1)=2(-5 1/3)=-10 2/3
f(x+1)=2(-10 2/3)=-21 1/3
f(x+1)=2(-21 1/3)=-42 2/3
x = 8
Solution:
Side-splitter theorem:
<em>If a line is parallel to one side of a triangle and the line intersects the other two sides, then this line divides those two sides proportionally.</em>

Do cross multiplication, we get
⇒ 4 × 42 = 21x
Divide by 21 on both sides, we get
⇒ 4 × 2 = x
⇒ 8 = x
Switch the sides.
⇒ x = 8
The value of x is 8.