the complete question in the attached figure
step 1
Find the distance of the center of the wall from the left end of the wall
distance=(1/2)*24--------> 12 ft
so
If x is the distance from a painting edge to its corresponding end of the wall, then
|x-12| is the distance from the painting edge to the center of the wall
and
If the painting is centered, then 2|x-12| represents the width of the painting
Since the painting is 10 ft wide,
we have 2|x-12|=10
therefore
the answer is the option B
2|x-12|=10