(1 point) Mike owns 7 different mathematics books and 4 different computer science books and wish to fill 5 positions on a shelf. If the first 2 positions are to be occupied by math books and the last 3 by computer science books, in how many ways can this be done

84 ways

Step-by-step explanation:

The order in which the books are positioned is not important, so we use the combinations formula to solve this question.

Combinations formula:

is the number of different combinations of x objects from a set of n elements, given by the following formula.

In how many ways can this be done

2 math books, from a set of 7.

3 computer science books, from a set of 4.

So

This can be done in 84 ways

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons