there is a question on the math section of a ManhattanPrep practice test that gives the following:
z^2-3z-4=0 --> so z=4 or -1
it then asks to compare A) z^2 to B) 12+2z
If you plug in 4 or -1 for both then in both cases Quantity B is bigger than Quantity A. What I don't understand is why you can only compare them with the same values, as opposed to using 4 to plug into A and -1 to plug into B.
If you use any possible value of z then you get cases where A is bigger and cases where B is bigger. I was inclined to answer this question saying you cant determine which one because of that, but the correct answer given was B only.
What is the rationale for only comparing with the same values when there are multiple possible values?