One yardstick for measuring how steadily—if slowly—athletic performance has improved is the mile run. In 1957, the local record for the running of a certain distance was 3 minutes, 59.2 seconds, or 239.2 seconds. In the half-century since then, the record has decreased by 0.4 seconds per year. a.) Express the record time for the mile run, M, as a function of the number of years after 1957, x.
b.) If this trend continues, in which year will someone run a 3-minute or 180-second, mile?

question is incomplete.

options a,b,c are the right answer.

step-by-step explanation:

a linear parent function is always represented as y = x

if we write this function in the form of y=mx+c

⇒

or  

now if we plot a graph we will find these characteristics:

1) y intercept of the graph is zero so its a straight line passing through origin.

2) as we can see in both the forms of function written, values of x and y may be either positive or negative for the positive slope means points on the graph are either in first quadrant or in third one.

3) it's slope is one.

the answer is d

step-by-step explanation: