When eliminationing in systems of equation, how do you know when to add or subtract?

Atransformation was performed on rectangle c as shown in the graph. what type of transformation was performed? does that transformation result in congruent shapes? you people

At a cost of 200, your club bought 175 frisbees to sell at the pep rally. you plan on selling them for $5 each. what is the domain of the function?

Captain umaima has a ship, the h.m.s. khan. the ship is two furlongs from the dread pirate nadia and her merciless band of thieves. the captain has probability 3/7 of hitting the pirate ship. the pirate only has one good eye, so she hits the captain's ship with probability 2/5. if both fire their cannons at the same time, what is the probability that the captain hits the pirate ship, but the pirate misses.