Please help Which expression does NOT have a Greatest Common Factor?

2x^2 +8x + 4
9x^4 + 2x^2 + 7x
9x^2 – 16
3x^2 – 12

Consider a bag that contains 220 coins of which 6 are rare indian pennies. for the given pair of events a and b, complete parts (a) and (b) below. a: when one of the 220 coins is randomly selected, it is one of the 6 indian pennies. b: when another one of the 220 coins is randomly selected (with replacement), it is also one of the 6 indian pennies. a. determine whether events a and b are independent or dependent. b. find p(a and b), the probability that events a and b both occur.