Math i need asap, . 25 points answer

Which coefficient matrix represents a system of linear equations that has a unique solution ? options in photo*

What is always true when two whole numbers are subtracted?

Consider an example of a deck of 52 cards: example set of 52 playing cards: 13 of each suit clubs, diamonds, hearts, and spades ace 2 3 4 5 6 7 8 9 10 jack queen king clubs diamonds hearts spades what is the probability of drawing three queens from a standard deck of cards, given that the first card drawn was a queen? assume that the cards are not replaced.