What countries are developing destructive or defensive weapons in space?

Anti-satellite weapons, which are primarily surface-to-space and air-to-space missiles, have been developed by the United States, the USSR/Russia, India and the People's Republic of China. Multiple test firings have been done with recent Chinese and U.S test program that destroy an orbiting satellite.

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

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