Step by step
The question
Question: solve x − 2 ≤ 5.
This is an inequality.
The sign means less than or equal to.
1 Remove the − 2
We want x by itself.
The − 2 is in the way.
To remove − 2, we add 2.
We do it on both sides.
Why both sides?
The sign compares the two sides.
If we change only one side, the answer can change.
− 2 and + 2 make zero.
Cross them out.
5 + 2 = 7.
So x is less than or equal to 7.
2 Show it on a number line
Books also write the answer like this.
It is called interval notation.
A square bracket means the end is in, like the filled circle.
∞ means it goes on for ever.
3 Check
Let's test one number from the answer: 6.
We put it in place of x.
First the left side.
Now the right side.
4 is less than or equal to 5.
True!
So the answer works.
Let's look back.
First: remove the − 2.
Then: show it on a number line.
Last: check.