Find the value of the constant a for which the polynomial x^3 + ax^2 -1 will have -1 as a root. (A root is a value of x such that the polynomial is equal to zero.)

As voters exit the polls, you ask a representative random sample of voters if they voted for a proposition. if the true percentage of voters who vote for the proposition is 63%, what is the probability that, in your sample, exactly 5 do not voted for the proposition before 2 voted for the proposition? the probability is