Answer:
In its simplest form the domain is all the values that go into a function, and the range is all the values that come out.
Step-by-step explanation:

If 2x+y=5, then y=5-2x, so he substituted 5-2x correctly.
x+4x=5x, so he combined like terms correctly.
If 5x-10=10, then 5x=10+10 -> 5x=20, so he subtracted 10 from the right side instead of adding 10 to the right side.
The answer is C.
Here's the correct solution:
Answer: y= 1.25x
Step-by-step explanation:
1/4 +1/4= 1/2
6g +6g= 12g
there is 12 grams of fat in 1/2 cup of cheese
The correct answer is the first option