y= 89.976e^{- 0.023t}wheret= Time Elapsed (minutes) and

y= Temperature Difference (in degrees)

(a) Use the exponential function to estimate the temperature differenceywhen 35 minutes have elapsed. Report your estimated temperature difference to the nearest tenth of a degree.Show work.

(b) How long will it take for the coffee to reach a temperature of 120 degrees? HINT: We first must find the value of y, which is C - 69. Therefore, y = 120 - 69 = 51. We now use this value of y=51 in the equation and then solve for t = time. Don't forget to follow the rules on solving an exponential equation. You are solving:51= 89.976e^{- 0.023t}:51= 89.976e^{- 0.023t}