Find −2(−2.8). You may find using a number line to be helpful.

First of all, there's a problem with the units. 54 inches is less than 1.4 meters,
so the rectangle can't possibly have a 15-meter side. I'm sure you meant that
the perimeter is 54 meters.
One of the other sides is also 15 meters, and the two remaining sides
are both 12 meters. (15 + 12 + 15 + 12) = 54 meters.