3
it’s just how far away that number is from zero
Answer:

Step-by-step explanation:


In the given question, it is given that, the cost of telephone call, s, is $0.75 plus $0.25 times the number of minutes .
And we have to put the given informationin algebraic expression .
For the cost of telephone call, we have to use s and for the number of minutes, we need to use t .
So the required expression is

2x+y-3z=12
2x=4z-y
x=2z-y/2
I believe the answer is 4.