Which equation is an identity?

a. 6m - 6 = 7m + 9 - m
b. 3w + 8 - w = 4w - 2(w - 4)
c. 8 - (6v + 7) = -6v - 1
d. 5y+5 = 5y-6

Given the following statements, which is the best

Logan wants to know how many skateboards have defective parts. he inspects 20,000 skateboards and keeps track of the number of defects per board. use his probability distribution table to find the expected value for defects on a skateboard.

Which must be true in order for the relationship △zyv ~ △xwv to be correct? zy ∥ wx ∠z ≅ ∠y and ∠w ≅ ∠x zv ≅ vy and wv ≅ vx ∠z ≅ ∠x and ∠w ≅ ∠y