>>10858064>could you state that x = y + 1 THEREFORE y = x - 1 as well?Only if you knew that x=y+1 and y=x-1 are both correct in the context of the problem. Mathematically, saying "x = y + 1 IF AND ONLY IF y = x - 1" will always be correct, but you couldnt use the term THEREFORE without being certain that both cases are true. For instance, if y=1 and x=5, then using THEREFORE would be incorrect, but using IF AND ONLY IF would be correct.
