The first thing we must do is to build the expression based on what we are told in the enunciation:
Jermaine has t subway tokens:
t
Karen has 4 more subway tokens than Jermaine
t + 4
Raul has 5 fewer subway tokens than Jermaine
t + 4 - 5 = t -1
the ratio of Karen's tokens to Raul's tokens
Ratio: (t + 4) / (t-1)
answer
Ratio: (t + 4) / (t-1)
I think the current age of the child is 16 and the father is 40. That would mean 4 years ago the father was 36 and the child was 12. This makes the father 3 times as old as his son four years ago.
First you subtract 3 from both sides so it would be: -5h = 30
Second you divide -5 from both sides so it would be: h = -6
Put the equation in y=mx+b format
Y=-4x-3y
Y+3y=-4x
4y=-4x
Y=-4/4x
Y=-x
The slope is -1
Hope this helps!