15 crates of egg costs #21,500 how many crates will #1500 buy?

Pls! does anybody know a shortcut for answering these types of questions in the future?

Which equation matches the graph shown ?

Which equation shows the quadratic formula used correctly to solve 5x2 + 3x -4 0 for x? cos -3+ v (3) 2-4() 2(5) 3+ |(3)² +4() 205) 3+ (3) 2-4() -3+ v (3)² +4()