The replacement set is .
Replace x in the equation with each value in the replacement set and check
\whether the equation is true or not.
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
x \ | \
| \
True or False \ |
\
11 \ | \
| \
False \ |
\
12 \ | \
| \
True \ |
\
13 \ | \
| \
False \ |
\
14 \ | \
| \
False \ |
\
15 \ | \
| \
False \ |
Since x = 12 makes the equation true, the solution of is 12.
The solution set is {12}.