h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Okay, so yesterday I did my first GCSE Maths exam, and it was okay, but whoever wrote the paper, steer clear, I'm planning on attatching the alternative segment theorem to a firework and shoving it where the sun don't shine.

Could someone please tell me what x and y equal if

y = x-7

and

x squared + y squared = 25

It's a simultaneous equation thing, and everytime I did it, I ended up having to find the square root of minus 12, and negative munbers don't have square roots.

So, you'd think todays GCSE English exam would have been fine, English is after all, a subject I'm very good at. But no, after starting 10 minutes late, the fire alarm went off 15 minutes in, so we had to evacuate the hall. Meaning that the exam had to be restarted half an hour late.

Still, no exams tomorrow, and a late start, which is good, because I'm not going to leave the theatre much before twenty to ten.

Not fun. Our group managed to set of the fire alarm during a HE parctical exam.

There are two solutions: x=3, y=4 and x=4, y=3. I'm guessing you made a mistake squaring (x-7) somewhere? Whatever you did, it'll be a silly mistake. You should get plenty of marks if you showed your working.

Anyway, it's done now - as is the English exam. Two less for you to have to think about now!

How did you do that!

You're right, because it told me what y equalled I squared the -7 and got 49, then minused the 49 away from the 25 to get x squared. So how are you supposed to do it?

I@m sorrry English didn't go to well honey disruptions in exams aren't good. Fire Alarm in particular. I was lucky and never had one...but we did have some t*sser running around the roof while I had my admin exam last year

Ok, starting from the two equations you're given:

1) y = x - 7
2) x^2 + y^2 = 25

(where x^2 means x squared)

If you've done a lot of Pythagoras, you might notice that (+/-)3^2 + (+/-)4^2 = (+/-)5^2 (9 + 16 = 25), which fits the equations.

However, under exam conditions, you probably wouldn't spot something like that. So:

y = x-7 means that y^2 = (x-7)^2 = x^2 - 14x + 49

If you put that in the second equation, you get x^2 + x^2 - 14x + 49 = 25

Which simplifies to 2x^2 - 14x + 24 = 0

You can factorise this (either by sight or using the quadratic formula) to: (2x-6)(x-4) = 0

So either x=3 or x=4.

Putting this into the first equations tells us that y=-4 or y=-3 (missed the '-' signs off last time!)

It's a long time since I did this stuff, but if memory serves then a minus number multiplied by another minus number equals a positive number. Thus, for example, -3 x -3 equals 9, not -9.

If I'm right, then x = 4 and y = -3 would produce the right answer.

Anyway, I sympathise. I did an exam a couple of weeks ago and thought that one of the exercises seemed to end rather abruptly. I looked at the page numbers on the exam paper, and sure enough there was a page missing.

Didn't they tell you at the start of the exam to read through the paper, and make sure it was all there? I'm fairly sure they did for all mine...

We were always told check that you have you paper with the right coding and date etc, you have the right answering paper and that you have everything filled out on the front before the exam starts. Then you read the casestudy or whatever twice and then answer the questions...that part I never agreed with, questions first then the case study so you can highlight any information and go back to it when you answer the questions....then again that's maybe just a dyslexic trick to avoid spending an hour of any exam reading and not answering.

I can't beilieve i got that wrong! I did x^2 -49, completely forgot about the 14x. And quadratic equations are about the only thing I can REALLY do!

If that's all you did wrong on that question, you should only drop a couple of marks if you showed all your working

Good, because it was worth 10 percent of the marks. Which is actually really stupid, because there must be a lot of people who would have found that question hopeless, and that's a massive chunk to lose.

10%??? How long was the exam (time-wise, I mean)?

Dare I ask what else was on the paper?

Wish my maths was still like that.

Anyway, not more maths for me forever now, had exam today. Was not that bad, and I got the fun of asking if one of the questions had a misprint, and they had to phone up the examiner and ask!

So was it a misprint?

*decides to put in her WE had a misprint in are paper, to be fair the last math test I sat was standard grade which must be A Level down south, but the trig question at the....

actually forget it, not interesting.

Ok, the paper was 1 and a quarter hours long, and covered the non-calculater aspects of algebra and shape, space and measure. It was worth 70 marks in total, and the simultaneous equation question was worth 7 marks. There were far too many questions on the alternative segment theorem, some iffy questions on vectors which I'd only managed to grasp the basics of, some nice stuff on bisecting lines, and algebraic equations. Oh, and the first questions was about exterior angles of a polygon, which I hadn't been taught. And all the higher tier stuff is self taught anyway, and I was learning right up until the exam because my teacher gave us the second piece of coursework alongside, and that had to take precedence, so I got really behind.

I was doing the higher tier as well, so if I don't get the minimum marks needed for a C, I'm automatically ungraded. I've told my Mum that I don't care what marks I get, I'm never doing maths again.

I've got the calculator paper for this module on Tuesday morning, and then the non calculator and calculater papers for handling data on Thursday, but they're only 25 mins each because it's a shorter topic. I was supposed to do them at the beginning of the year, but couldn't due to my anaemia.

That's got to be a contender for longest post surely?

nope unfortunately

Jeepers! I only actually wrote that last comment for a laugh. What's the link for the page that says whose posted the longest etc?

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