Answer:
A.
Step-by-step explanation:
This is because you can plug in the two hourly costs into each of the answer choices to check if you are right. Since x stands for x amount of hours, you can plug in the hours you are given into each of the equations and replace C(x) with the cost ($).
A.) C(x)=300x+200
Plugging it in with the first equation, 1100=300(3)+200, that equals to 1100=900+200 and simplified makes 1100=1100.
Plugging in the second equation, 1700=300(5)+200, that equals to 1700=1500+200, making 1700=1700. Making both points fit with the equation. But let's check the other equations.
B.) C(x)=500x-800, using the first point, 1100=500(3)-800. 1100=1500-800, which simplifies to 1100=700. This is not true, thus B cannot be the right answer.
C.) C(x)=400x-100, to save time I'll skip to using the second point. 1700=400(5)-100, turning into 1700=2000-100, which is 1700=1900, and 1900 doesn't equal 1700, so C is wrong as well.
D.) C(x)=200x+700: 1100=200(3)+700, that makes 1100=600+700, which is 1100=1300. This makes D invalid as well.
Checking all the equations, we know that the answer is A.
