Let's build the equation counting how many x's and 1's are there on each side.
On the left hand side we have 5x's and 8 1's, for a total of 
On the left hand side we have 3x's and 10 1's, for a total of 
So, the equation we want to solve is

Subtract 3x from both sides:

Subtract 8 from both sides:

Divide both sides by 2:

Answer:
n=6
Step-by-step explanation:
(n-18)/3 = -4
multiply by 3
n-18 = -12
add 18
n = 6
Answer:
C
Step-by-step explanation:
a-b-c
-3-4-(-5)
-3-4+5 [as - - = +]
-2
Answer:
the cost of each pen is 1.33
Step-by-step explanation:
if you multiply 0.75 by 8 you get 6 after that you subtract 6 from 12.65 which means you have 6.65 which you divide by 5 which equals 1.33
F(x) = 2 x - 5
15 = 2 x - 5
2 x - 5 = 15
2 x = 15 + 5
2 x = 20
x = 20 / 2
x = 10
hope this helps!