Determining a value of an expression

To evaluate an algebraic expression, you have to substitute a number for each variable and perform the arithmetic operations.

I think.

Yes

Step-by-step explanation: For any horizontal or flat line, the slope will always be the same which simplify to 0.

Let's look at an example which I have provided in the first image attached. I have labeled two points on the line and they are point A and point B.

To get from point A to point B along this line, our rise is 0 units and our run is 3 units so our slope or rise over run is 0/3. However, 0/3 can be simplified to 0. So for this line, our slope or m equals 0.