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Joshua Capel on Reversed subtraction 2 years ago
When the fractions are not equivalent in part (b) they are of the form z=(a-b)/(c-d) and z=(b-a)/(d+c) respectively.
In this case the answer requires the selection of the option "not equivalent! One is the negative of the other.", but this is not true.
I think the option "not equivalent! One is the negative of the other." should be incorrect in both cases (but this will change the number of correct options between the two types of question).