Y axis is going up by 25 X axis is going up by 1

The equation of trend line is y = 5x + 23.
Substitute 3.5 for x in the equation to determine the temperature after 3.5 minutes.
[tex]\begin{gathered} y=5\cdot3.5+23 \\ =17.5+23 \\ =40.5 \end{gathered}[/tex]So answer is 40.5.