how did you do this question? (OL Maths Q 2b)

Mwah

ord level maths 1
question 2b

was

2x-y=1
x2-xy=-6

ive never seen it with a number infront..

i got like

2x=1-y

and didnt kno were to put it in (lol)

MaggieNF

Get y on its own so you get 2x - 1 or whatever then sub that in

calleochosam

x= 1-y/2( I think ya have to make it a fraction!):)

dodgystuff

I got this after about 3 attempts

2x-y=1
x2-xy=-6

you isolate the y in the top line (so y = blah blah) and fill in the y value in the second and you get 2 values for x and then fill them both into either line and you get y values

that's what i did anyway!

EuropeanSon

is that an x squared? If so, you do this.
-xy=-6-x2
y=(6+x2)/x

then sub for y in the other Eqn.

PARARORY

ord level maths 1
question 2b

was

2x-y=1
x2-xy=-6

ive never seen it with a number infront..

i got like

2x=1-y

bring the y over the other side of the equals sign.

now you have y= 2x - 1

Sub y into the second equation.

x2 -x(2x-1) +6 = 0

x2 -2x2 + x + 6

tidy it up and ya get x2 -x -6

use a quad trinomial.

(x-3 ) (x + 2 )

x = 3 and x = -2

find the coreesponding y values by subbing them in...

Mayoegian

PARARORY wrote: »

bring the y over the other side of the equals sign.

now you have y= 2x - 1

Sub y into the second equation.

x2 -x(2x-1) +6 = 0

x2 -2x2 + x + 6

tidy it up and ya get x2 -x -6

use a quad trinomial.

(x-3 ) (x + 2 )

x = 3 and x = -2

find the coreesponding y values by subbing them in...

And you should get 5, -5 for the 2 y values!:)

0.M.GXX

this question breally got to me 2.. question 2 was the first question i did.. because i cannot do question one..
so i thought it would be ok.. but i spend a good 15mins trying to get it out.. and with about four attempts.. very annoying really but i did it..
#2x-y=1
1) separate the y from the rest...
-y=1-2x
2) then change the sign of y by multiplying by (-1)
y=-1+2x
3) i subbed it back into the equation
x^2-xy=-6
4) i got 2 answers which.. i cant member.. but they second x value was weird .. then i got y values for them...
i dont know if this is the corrrect way .. but i hope it is...
very hard paper wsnt it especially the differenation... what did people think about the first principle...?

Viva La Cozzy

i was the same i didn't have a clue
you can't divide 1 + y by 2
what i did was i filled in 1+y/2 in to the bottom equation and worked it out as far as i could, i hope i got some marks for it

stainluss

PARARORY wrote: »

bring the y over the other side of the equals sign.

now you have y= 2x - 1

Sub y into the second equation.

x2 -x(2x-1) +6 = 0

x2 -2x2 + x + 6

tidy it up and ya get x2 -x -6

use a quad trinomial.

(x-3 ) (x + 2 )

x = 3 and x = -2

find the coreesponding y values by subbing them in...

I did half of that and then crossed it out (Its still visible though)

I then put everything in terms of X.

Would I get any marks?

PARARORY

I did half of that and then crossed it out (Its still visible though)

I then put everything in terms of X.

Would I get any marks?

it its still visible they will see you were on the right track and yeh you will definitely get some marks... I think you could get about 7/10 marks , usually 3 marks goes for the answer (I think)

shocxxxxxx

fu*kin brainiacs! I glanced at it and laughed at the thought of even attemptin it!

seanbmc

I aced this question, was really happy with myself

DB10

Anyone know how to Q 1 C ii??

PARARORY

So happy with this paper now...

the above part was worth 20 marks.

The guy on 2fm is saying about the paper that it suited ex honours students!
Ordinary

3 c - the ahrdest part by far " it would be very hard to justify putting that on the ordinary course " , "whoever set this questions hasnt been teaching leaving cert pass for years "

Ha woooo - it looks like the marking schemes could be changed!

hokeypokey

Easy peasy!

stainluss

PARARORY wrote: »

Ha woooo - it looks like the marking schemes could be changed!

You mean they could be a lot sounder when giving marks to us?:eek:

Sl!mCharles

That's uplifting:D

Danger781

DB10 wrote: »

Anyone know how to Q 1 C ii??

The answer was €5500 @ 4% per annum

228.80

---

= 1.04
220

Therefore €220 = 4%

220 ÷ 4 x 100 = €5500

R=4%
P=€5500

Danger781

PARARORY wrote: »

So happy with this paper now...

the above part was worth 20 marks.

The guy on 2fm is saying about the paper that it suited ex honours students!
Ordinary

3 c - the ahrdest part by far " it would be very hard to justify putting that on the ordinary course " , "whoever set this questions hasnt been teaching leaving cert pass for years "

Ha woooo - it looks like the marking schemes could be changed!

What the hell? That was not a difficult question.. It was fairly obvious what to do..

neiler987

meh dont really agree !!

really looks like they made it more difficult ti get an A or B but much easier

for ppl ti get a D who are struggling ?

Conor108

PARARORY wrote: »

x = 3 and x = -2

find the coreesponding y values by subbing them in...

Wow I've been worried since I left the hall but I got this correct then! Can't believe it thought I was WAY off

Danger781

Actually what about Q3(b)

I used the '-b formula' and ended up with -1.8 and 0.22

Anyone else?

Here's the paper if anyone else wants to look:
http://examinations.ie/archive/exampapers/2010/LC003GLP100EV.pdf

Conor108

Would be so handy if they prepared the marking schemes at the same time as the papers and stuck them up on examinations.ie

Danger781

Conor108 wrote: »

Would be so handy if they prepared the marking schemes at the same time as the papers and stuck them up on examinations.ie

Thats what I was thinking, but then we'd know what we got before the examiners :rolleyes: People would be trying to guesstimate points and what not.. Just isn't helpful to anyone..

Edit: Also the marking scheme can be changed

PARARORY

Actually what about Q3(b)

I used the '-b formula' and ended up with -1.8 and 0.22

Anyone else?

I got the same and so did about 5 other of my friends , we all though the answer was strange though? Maybe a mistake in the question on the paper someone said?

Danger781

PARARORY wrote: »

I got the same and so did about 5 other of my friends , we all though the answer was strange though? Maybe a mistake in the question on the paper someone said?

i dunno but when I subbed in my answer I ended up with 0.0000000002 or something.. So I assumed it was correct

Mr Cawley

Changed? you're not serious?

Conor108

Well its graded to a curve so yeah they can change it.

Like say 99% of the country failed a part of a question I think they just go and give any attempt full marks...or partial marks...or something anyway!

stainluss

Im after looking at another marking scheme for a similar question (3b 2006) and it says to apply the 'structure' whether x or y is isolated, so maybe its grand doing it either way, despite one way being harder (can't even remember which anymore)

Danger781

Yeah they can change it to suit the results.. They want to get around the same thing every year..