Linear relations are used to find the relationship between 2 variables (usually on a graph)
For example, if you have 5, 8, 11, 14 the relationship would be +3.
If you want to find higher numbers in this pattern you insert the numbers in a table of values (usually on the y side)
You match them with X numbers (usually 1, 2, 3…)
Since you added 3, you start the equation with 3x, then you calculate that. 1 would be with 5 so you go 1 x 3 =3, but thats not five so you still need to add 2 to get your answer so the equation would be 3x + 2.
If you want to find the Y value for X=22, then you replace X with 22 (22 x 3 +2 =68) and 22 would go with 68
You can use linear relations to add point to a graph, independent variable is on the X axis and the dependent variable is the Y axis.
Continuous variables are things you can measure like time, age, kilometers and you connect these dots on a graph.
Discrete variables are used when you are counting something like cars, shoes or people and you do not connect these dots on a graph.
