Modeling with Linear Equations

There was several questions ask from my algebra class as a homework which I am having difficulty answering. Please help me solve for them thanks.

The equation y = 1.13x + 7.85 represents the average monthly cost in dollars for cable television where x represents the number of years after 1980. Use this equation to answer the following questions.

1. What is the input variable? what does it represent? What units is it measure in?

My best attempt to answer this is that the input variable is x. It represents the numberof years after 1980 for example 1981, 1982 etc. It is measured in the units of years.

2. What is the output variable? what does it represent? What units is it measure in?

My best attempt to answer this is that the otput variable is y. It represents the average monthly cost in dollars for cable television. It is measured in the units of dollars.

3.According to this model, what is the average monthly costs in dollars for cable television in 2000?

y = 1.13x + 7.85
y = 1.13(2000) + 7.85
Y = $2,267.85
2,267.85/12 = 188 PER MONTH

4. According to this model, in what year will average monthly costs reach $40?

5. What is the y-intercept of the graph of this question? what is its meaning in the context of this model?

6. What is the slope of the graph of this question? what is its meaning in the contextf this model?

7. what is a reasonable domain for this model?

8. What is a reasonable range for this model?