Assuming a linear relationship between X and Y, find the slope of the line to write down an equation of the form:
![y=mx+b](https://img.qammunity.org/2023/formulas/mathematics/high-school/smsb8cbft03lwblmi49nf2l6jby2ofxzws.png)
where m is the slope of the line and b is the y-intercept.
Take two pairs of values to calculate the slope. Use the pairs (2,8) and (4,14):
![\begin{gathered} m=(\Delta y)/(\Delta x) \\ =(14-8)/(4-2) \\ =(6)/(2) \\ =3 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/9eabfyl1iz9wl0ztoqxw0cf7yryod3h4ba.png)
Substitute m=3 into the equation, as well as the values of one of the pairs. Take x=2 and y=8. You can then find the value of b:
![\begin{gathered} 8=3(2)+b \\ =6+b \\ \Rightarrow b=2 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/19xu66kpo661jfcmaxbsjo0mwo0eg33vb9.png)
Substitute b=2 and m=3 to find the equation of that linear relation:
![y=3x+2](https://img.qammunity.org/2023/formulas/mathematics/high-school/tv1b4lf1wzjacd3ylloo16ftgphjj3vzip.png)
Substitute x=7 to find the missing value of y:
![\begin{gathered} y=3\cdot7+2 \\ =21+2 \\ =23 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/p3i29dap5kdu63t6pda076orouk6ai0m21.png)
Therefore, the equation of the table is y=3x+2 and the missing value of y when x=7 is 23.