Planes M and N intersect at line d. Line a forms a right angle with line d. Line b is diagonal and crosses line d. Line c is on plane N and is diagonal. Line e is on plane M and is slightly diagonal at the top of the plane. Which are skew lines? Check all that apply. a and b c and b b and e e and c a and e a and c

Exercise: counting committees 0.0/2.0 puntos (calificable) we start with a pool of n people. a chaired committee consists of k≥1 members, out of whom one member is designated as the chairperson. the expression k(nk) can be interpreted as the number of possible chaired committees with k members. this is because we have (nk) choices for the k members, and once the members are chosen, there are then k choices for the chairperson. thus, c=∑k=1nk(nk) is the total number of possible chaired committees of any size. find the value of c (as a function of n ) by thinking about a different way of forming a chaired committee: first choose the chairperson, then choose the other members of the committee. the answer is of the form c=(α+nβ)2γn+δ. what are the values of α , β , γ , and δ ?