Guys i need help with this

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?

Iwant to know what 3g+5h+4g-2h is my teacher is too selfish to tell us

Which ordered pair (c,d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15