Oxford PAT 2012, Question 11

2012_page12

8 thoughts on “Oxford PAT 2012, Question 11

    1. Hi, thanks for your question.

      In order to get the two equations labelled (a) and (b) in the answer, we multiply both sides of each inequality by x. When we multiply both sides of an inequality by a negative number we need to flip the inequality. So when we are considering the cases where x is negative, and we multiply both sides by x, we need to flip the inequality.

      If you’re having trouble with this as a concept, you are not alone: if you google the words inequality multiply negative, you’ll find various attempts at explaining this in ‘intuitive’ ways.

      I hope this helps. If you need more clarification then please add another comment. And good luck with the exam!

      1. Hi, thank you for your quick reply.

        I understand the multiplication rule regarding inequalities, however when I done this question, I did not multiply anything by negative and ended up with inequalities:

        -1/2 < x x > -1
        compared with your
        1/2 < x x > -1

        Which is very similar but not the same. Why did you ‘swap’ your 1/2’s? Or what did you do instead?

        Many thanks!

      2. These comments are not allowing me to display my inequalities, but mine are basically same as your but the 1/2’s are opposite signs, so your positive half would be my negative.

        Sorry.

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