Calculating Permutations A teacher has four books—A, B, C, and D—to assign to four students in any order he prefers
Set S includes all possible arrangements of the four books
Set X includes all possible arrangements when book C is chosen first and D is chosen second.
Which notation is correct?
If book C is chosen first and D is chosen second, in how many ways can the teacher assign the books?

(2x + 16) + (x) = 180

step-by-step explanation:

given,

abcd is a quadrilateral inscribed in a circle

angle a is labeled x plus 16, (x + 16)

angle b is labeled x degrees, (x)

angle c is labeled 6x minus 4, (6x – 4)

angle d is labeled 2x plus 16, (2x + 16)

what equation can be used to solve for angle b?

we know that the sum of the opposite angles of a simple quadrilateral inscribed in a circle is 180 degrees.

angle b is opposite angle d

therefore, angle b + angle d = 180

(x) + (2x + 16) = 180 

same as (2x + 16) + (x) = 180

explanation:

step-by-step explanation:

3 3 6, because in every triangle the longer side is always shorter than the sum of the other two