Let "x" represent the age of Brian.
Andrew is elder than Brian by 2 years, we can symbolize his age as "x+2"
Frank is twice as old as Andrew, we can symbolize his age as "2(x+2)"
Sarah has half the age of Brian's, we can symbolize her age as "x/2"
Frank ans Sarah's ages differ by 40 years, we can symbolize this as:

Solve the term is parenthesis

x=24 years
Andrew's age is

Andrew is 26 years old
The slope is 3
whatever is in front of the x is the slope
Answer:
I think it's non linear because the 1 to 1 wouldn't work