Answer: x > 6
The graph is shown below.
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Step-by-step explanation:
We want to get x by itself. To do this we subtract 9 from both sides.
This is to undo the +9
x+9 > 15
x+9-9 > 15-9
x > 6
This describes all numbers larger than 6. To visually show this on a number line, we have an open circle at 6 and shading to the right.
The open circle is to exclude the endpoint from the solution set.
If the solution set consists of integers only then it would be {7, 8, 9, ...}