Answer:
6x12
Step-by-step explanation:
Use a system of equations:
For his trip on the way there:
D = 7*s
For his trip on the way home you have:
D = 5*(s+18)
use substitution to solve
Answer:

Step-by-step explanation:
Given the expression

Follow the PEMDAS order of operations

calculate within parentheses 

calculate exponents

Multiply and divide (left to right)

Add and subtract (left to right) 

Thus,

Answer:
v(t)=(-6,000)(years)+80,000
Step-by-step explanation: