The larger number is (-7+14)/2 = 3.5.
The smaller number is (-7-14)/2 = -10.5.
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The two equations a+b=-7, a-b=14 can be solved to get these results. It is genrally convenient to solve them by adding one to the other, or subtracting one from the other.
The perimeter should be about 66
The company will have a total number of 531 employees