May I please get help

Evaluate the expression for the given value of the variable 2×(c2-5) for c=4

Aclassroom is made up of 11 boys and 14 girls. the teacher has four main classroom responsibilities that she wants to hand out to four different students (one for each of the four students). if the teacher chooses 4 of the students at random, then what is the probability that the four students chosen to complete the responsibilities will be all boys?

Rob filled 5 fewer plastic boxes with football cards than basketball cards. he filled 11 boxes with basketball cards.