Which of the following are solutions to the equation below 4x^2-81=0

(a) (8%) compute the probability of an even integer among the 100 integers 1! , 2! , 3! , until 100! (here n! is n factorial or n*(n-1)*(n-2) *… 1) (b) (16%) compute the probability of an even integer among the 100 integers: 1, 1+2, 1+2+3, 1+2+3+4, …., 1+2+3+… + 99, and 1+2+3+… + 100

The measure of one angle of an octagon is two times smaller that of the other seven angles. what is the measure of each angle?

The volume of a sphere is increased by 6%. calculate the corresponding percentage increased in it area.