Write a linear equation that describes the value y (in dollars) of the mri machine in terms of the time t (in years), 0 ≤ t ≤ 9.

For this case you could write a generic linear equation that determines the value in dollars after a number of years corresponding to the interval [0, 9]. Writing the equation we have

y = a * t + b with t [0, 9]

where,

a and b with constants that belong to the real numbers

t: it's time in years

y: the value in dollars of the mri machine.

answer:

y = a * t + b with t [0, 9]