The tables below give the numbers of some species of threatened and endangered wildlife in the United States and in foreign countries in 2015.

(a) Write a matrix A that contains the number of each of these species in the United States in 2015 and a matrix B that contains the number of each of these species outside the United States in 2015.

(b) Find a matrix with the total number of these species. Assume that U.S. and foreign species are different.

(c) Find the matrix B 2 A. What do the negative entries in matrix B 2 A mean?

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United States Mammals Birds Reptiles Amphibians Fishes Endangered 74 79 14 20 93 Threatened 27 21 23 15 70 Foreign Mammals Birds Reptiles Amphibians Fishes Endangered 253 Threatened 214 69 8 19 20 17 20 1 3