-0.8x + 5.2 < 0
-0.8x < -5.2
Remember- when multiplying or dividing a negative with < or >, you have to flip the < or > to the opposite symbol.
x > 5.2/0.8
x > 6.5
A set is a list of things inside braces. { these are braces }
A set can be a list of anything. The set of my genders is {male}. The set of all ages (in years) that I've ever been is {0, 1, 2, . . . 43}.
A solution set is a set describing all possible solutions to an equation, inequality, etc..
If we have x > 6.5, then the solution set is {all x such that x > 6.5} or (math-y way of writing it) {x : x > 6.5}