That is true, if we talk about x = (d – b)/(a – c), but would it be true if we considered the previous step x(a – c) = d – b ? Here, a – c can be 0. If we want to divide by it, we need to consider the case a – c = 0 separately. If a – c = 0, then 0 = d – b and the equality, 0 × x = 0, holds true for any x. That's exactly what we need, because the equality must be true for any value of x, while x = (d – b)/(a – c) gives us a constant instead of a variable, which can be any number, (of course, if a - c would not be 0).
Users browsing this forum: No registered users and 3 guests
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum
GMAT(TM) and GMAT CAT (TM) are registered trademarks of the Graduate Management Admission Council(TM). The Graduate Management Admission Council(TM) does not endorse, nor is affiliated in any way with the owner or any content of this site.