Out of  {(-3, -2), (-3, 0), (-1, 2), (1, 2)} what numbers are domain

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

Which graph represents the given linear function 4x+2y=3

The value, v, of kalani’s stock investments over a time period, x, can be determined using the equation v=750(0.80)^-x. what is the rate of increase or decrease associated with this account? 20% decrease 20% increase 25% decrease 25% increase