Question

Which expression is NOT equivalent to the other 3 expressions

(Yall I have no idea what my teacher talking about )
A: 6z + z - 1
B: 6z - 1 - z
C: 6z - (1+z)
(6z - 1) + z

Answer 1

A: 6z + z - 1 = 7z - 1
B: 6z - 1 - z = (6z - z) -1 = 5z -1
C: 6z - (1 +z) =6z - 1 - z =(6z - z) - 1 = 5z - 1
The last : (6z-1) +z = 6z - 1 +z =(6z + z) - 1 =7z - 1
=> The expression A = The last expression
=> The expression B = The expression C
=> Can’t know which expression is NOT equivalent to the other 3 expressions.

Answer 2

(B) 6z - 1 - z

Explanation:

Looking at the expression (6z - 1) + z, all of them are equivalent besides b because we are subtracting z instead of adding z.