Answer
A=-2b+48
Work Step by Step
First we decided that our y-intercept is 48 because that is the initial amount of vanilla we start with. Then we have -2 as our slope because each time we make a batch of cookies (b), we lose 2 teaspoons of our vanilla. The negative slope means that we are loosing two teaspoons and not gaining.
So therefore we come up with the equations:
A=-2b+48
