If bob give me 500 dollar to buy a seat for 200 what will be the change left

Does anyone know the answers to these two? i don’t want to have to guess, you!

Me i need a correct answer how did mlk jr.’s “voice” in his speeches shape the civil rights movement?

What effect is created by the plaque posted on the gate at the entrance to the family's home in nadine gordimer's "once upon a time"? the words written on the plaque offer readers a foreshadowing of the story's outcome without revealing the actual conclusion, the author's use of flashback allows readers to understand what is at the heart of the issues of encroachment in the suburban neighborhood the repetition of the words written on the plaque presents an oxymoron because readers already sense that the plaque has been ineffective in warding off intruders. the author introduces a paradox in which readers are presented with a warning notice when no actual infraction has taken place.