Write the equation of a function h (t) that represents the amount of heat in joules required to heat the bar to a temperature of t degrees Celsius.

The initial temperature of the bar is 25. To get to the t temperature you need to add (t-25) degrees Celsius.

for 1 degree ... 7 Joules

y given degree ... p Joules

p=7y

In our case y = (t-25).

h (t) = 7 (t-25) which is the final answer.