Q36: If x and y are integers, is y an even integer? (1) 2y – x = x2 – y2 (2) x is an odd integer.
first, assumed X is even, then 2y-x even, X2 even, so Y even
second,assumed x is odd, then 2y-x odd, x2 odd, so Y still even
Q22 from (1), get X<0
from (2) y=(20-2x)/5, so -2x>3/5(20-2x), so x<-15
answer is D
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