The question below was on my mgmat practice test. The answer is A, but my question has to do with the explanation. It is given that z - 2y = 3, but how? In working this problem out, I got -3 not +3. Is it +3 (and if so how) or is this an error?

If x + 2y = z, what is the value of x?

(1) 3y = 4.5 + 1.5z

(2) y = 2

If we solve the equation x + 2y = z in terms of x, we can rephrase the question.
x = z – 2y
The question becomes "What is z - 2y ?"

(1) SUFFICIENT: We can manipulate this statement to solve for z – 2y:
3y = 4.5 + 1.5z divide both sides by 1.5
2y = 3 + z
z – 2y = 3

You are absolutely right! It's a typo; it should say -3. Thanks for the catch!