Let V=R3 and let H be the subset of V of all points on the plane −5x−7y+2z=0. Is H a subspace of the vector space V?

On friday, there were x students at the baseball game. on monday, there were half as many students at the game as there were on friday. on wednesday, there were 32 fewer students at the game as there were on friday. which expression could represent the total number of tickets sold for all 3 games?