Discussion
Solve inequalities just like you would solve equations. There are two very
important differences.
1. Instead of a single element in the solution set that you would get with
a linear equation in a single variable, with an inequality you get a solution
set with an infinite number of elements represented by a number line interval.
2. When, in the process of solving the inequality, you need to multiply or
divide by a negative number, you must reverse the sense of the inequality.
Here's why:
, but
because
.
Solution
Just like an equation, you can add the same value to both sides:
Therefore, the solution set is all real numbers such that
Check Answer
The solution interval says that
is a solution, so check:
Is
a true statement? Yes,
The solution interval implies that anything smaller than 16 is a solution:
Is
a true statement? Yes,
The solution interval implies that anything larger than 16 is NOT a solution:
Is
a false statement? Yes, 12 is NOT less than or equal to 11.
Answer checks.