What do I write for the solution?

The solution would be any values that both lines satisfy, or in other words, any intersections.

x = 3

y = -2

Step-by-step explanation:

You can use substitution or elimination to solve for the solution, or simply just look at the graph and identify any intersections. In this case, the solution would be x = 3 and y = -2 or (3, -2)

Imagine we are to express  [ a , b ]  in set notation

A = [ a , b ] , then  A = { x  ∈  R  /  a ≤ x ≤ b }

In this notation we define the characteristics of all  x  belonging to this set  A x must be greater or equal to a and simultaneously smaller or equal to b...

Interval notation is other way to say the same but assuming that  means the extreme a is IN the interval and  means extreme  a  is not.