Solve the equation for x 1/3•x=20

Use the normal approximation to the binomial distribution to answer this question. fifteen percent of all students at a large university are absent on mondays. if a random sample of 12 names is called on a monday, what is the probability that four students are absent?

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

If f(x) = 3x2 - 2x+4 and g(x) = 5x + 6x - 8, find (f-g)(x).