Three and more points are collinear
You are correct! The problems that can arise with a function domain are:
- Denominators that become zero
- Even-degree roots with negative input
- Logarithms with negative or zero input
In this case, you have a denominator, and you don't have roots nor logarithms. This means that your only concern must be the denominator, specifically, it cannot be zero.
And you simply have

So, the domain of this function includes every number except 3.
Take the co-ordinates of your triangle and add three to the Y co-ordinates and keep the X co-ordinates the same. Then, graph. The shape should have slid upwards three points.
Answer: 5 cookies
Step-by-step explanation: 8 + .4c = 2.5 + 1.5c
8 + 0.4c = 2.5 + 1.5c
8 · 10 + 0.4c · 10 = 2.5 · 10 + 1.5c · 10
80 + 4c = 25 + 15c
4c = 15c - 55
4c - 15c = 15c - 55 - 15c
-11c = -55
c = 5
Not 100 % but I would think as likely as not because you have the same amount of both. 1/2 the chance