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Part b) of this question to find the points of intersection of $y = |2x+3| - 4$ and $ y=-\frac{1}{4}x + 2$

problem

However, in the given answer set, they seemed to have ignored the $-4$ constant in the first equation:

examiner answer

I have no idea why they would do this, and thus I got an different answer to that of the mark scheme. Am I wrong or is the examiner?

0.5772156649
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  • https://www.wolframalpha.com/input/?i=%7C2x+%2B+3%7C+-+4+%3D+-1%2F4+x+%2B+2. You can use the answer and see if it satisfies the LHS and RHS. Neither result does - the answers are wrong! It looks like he solved this problem instead: https://www.wolframalpha.com/input/?i=%7C2x+%2B+3%7C+-+4+%3D+-1%2F4+x+-+2, $$|2x + 3| - 4 = -1/4 x - 2$$ – Moo Mar 13 '20 at 20:27
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    So, you are saying they just made a mistake, and it evaded the proof-reader(s)? Because I have thought this about mark-schemes before, and it has turned not to be the case. However, with this, I don't see any alternative explanation. – 0.5772156649 Mar 13 '20 at 20:32
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    It should be $-2$ instead of $+ 2$ for their result. Sign errors suck, it happens and this problem statement does not satisfy the result! Yes, they screwed up, it happens all the time! – Moo Mar 13 '20 at 20:33
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    Yes, the answer is incorrect. THis happens. – fleablood Mar 13 '20 at 20:40

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