What is the missing reason for line 3 in this proof? Given : LM = 12 ; LZ = 3x ; MZ = x

Prove : LZ = 9

A.
addition property of =
B.
substitution property of =
C.
definition of segment bisector
D.
segment addition postulate

Using d, e, and f as values on a triangle and d being 60 degrees, what is the value of e and f if d is 60 degrees? also, what do you notice about the values of e and f?

Abox of chocolates costs $7. which equation relates the number of boxes sold (x) and total cost of the boxes sold (y)?

Delbert keeps track of total of the total number of points he earns on homework assignments, each of which is worth 60 points. at the end of the semester he has 810 points. write an equation for delbert’s average homework score a in terms of the number of assignments n.