EXAMPLE: If four coins are flipped, what is the probability of getting two heads and two tails?

YOU TRY: If three coins are flipped, what is the probability of getting one heads and two tails?

EXAMPLE: When $$\left(x+1\right)^4$$ is expanded, the fourth term is ______.

YOU TRY: When $$\left(x+1\right)^5$$ is expanded, the third term is ______.

EXAMPLE: When $$\left(2x-1\right)^3$$ is expanded, the second term is ______.

EXAMPLE: When $$\left(3x-1\right)^4$$ is expanded, the second term is ______.

EXAMPLE: There are 7 terms in the expansion of $$\left(3x-y\right)^{2n}$$ .  Determine the value of n.