Please help with #27 and please explain

Answer:
(a) 3 added to twice the value of n
(b) [tex]T = 2n +3[/tex]
Step-by-step explanation:
Given
Table #27
Solving (a): First, we express as an equation
The table illustrates a linear function; so, we calculate the slope (m) first
[tex]m = \frac{T_2 - T_1}{n_2 -n_1}[/tex]
Where:
[tex](n_1.T_1) = (4,11)[/tex]
[tex](n_2.T_2) = (8,19)[/tex]
So:
[tex]m = \frac{T_2 - T_1}{n_2 -n_1}[/tex]
[tex]m = \frac{19 - 11}{8-4}[/tex]
[tex]m = \frac{8}{4}[/tex]
[tex]m = 2[/tex]
The equation is then calculated using:
[tex]T = m(n - n_1) + T_1[/tex]
[tex]T = 2(n - 4) + 11[/tex]
[tex]T = 2n - 8 + 11[/tex]
[tex]T = 2n +3[/tex]
In words, the equation is: 3 added to twice the value of n
Solving (b): As an equation.
This has been solved in (a) above:
[tex]T = 2n +3[/tex]