You are Here: Home

# GCSE Question Tweet

Maths exam discussion - share revision tips in preparation for GCSE, A Level and other maths exams and discuss how they went afterwards.

Announcements Posted on
Enter our travel-writing competition for the chance to win a Nikon 1 J3 camera 20-05-2013
IMPORTANT: You must wait until midnight (morning exams)/4.30AM (afternoon exams) to discuss Edexcel exams and until 1pm/6pm the following day for STEP and IB exams. Please read before posting, including for rules for practical and oral exams. 28-04-2013
1. GCSE Question
Q1. rearange S=2pidsqrthh^2+d^2 i need to make h the subject.

so far i've got s^2=(2pid)^2 (h^2+d^2)

i'm not sure if i'm doing it correctly.

Q2. solve the equation

7/x+2 + 1/x-1 = 4

so far i've got

7x-7 = 4x^2+4x-8 then 4x2-3x-1=0

factorised it

-3+or-(sqrt3^2-4x4x-1)/8

i got x = 0.25 or -1 which i think is wrong.

Q3. bag contains 6 red disks, 4 blue disks and 5 green disks.
A fair dice has 4 red faces and 2 blue faces.

a disk is taken at random from bag and the colour is recorded.
then dice is thrown twice and each time colour of face it lands on is recorded.

work out probability that, of the three colours that are recorded, exactly 2 are the same.
Last edited by non; 19-06-2012 at 22:51.
2. Re: GCSE Question
For question two wouldn't you * the botoms by eachother
3. Re: GCSE Question
(Original post by Mrbawby)
For question two wouldn't you * the botoms by eachother
i'm not sure sorry.
4. Re: GCSE Question
7/x+2+1/x-1=4
(x-1). (x+2)
(7x-7)+(x+2)/(x+2)(x-1)=4
7x-7=4x-4
7x=4x+3
3x=3
X=1
Btw i havent started unit 2 so it may be wrong
Last edited by Mrbawby; 20-06-2012 at 00:01.
5. Re: GCSE Question
(Original post by Mrbawby)
7/x+2+1/x-1=4
(x-1). (x+2)
(7x-7)+(x+2)/(x+2)(x-1)=4
7x-7=4x-4

7x=4x+3
3x=3
X=1
Btw i havent started unit 2 so it may be wrong
You have to multiply the 4 by (x-1)(x+2) too.

And you can't cancel out (x+2) in the lines in bold
Last edited by usycool1; 20-06-2012 at 20:24.
6. Re: GCSE Question
Nope, i *7 by x-1 and 1 by x+2 buy like i said i may be wrong
7. Re: GCSE Question
(Original post by Mrbawby)
Nope, i *7 by x-1 and 1 by x+2 buy like i said i may be wrong
Ah, I see. You have to multiply the 4 by (x-1)(x+2) too
8. Re: GCSE Question
Uh you sure 7(x-1)+1(x+2)/x^2+x-2=4 right? Mind doing the question for us
9. Re: GCSE Question
(Original post by Mrbawby)
Uh you sure 7(x-1)+1(x+2)/x^2+x-2=4 right? Mind doing the question for us
I'll post a different example and you guys can try the original question on your own

Spoiler:
Show

Multiply everything by (x+7)(x+4):

Simplify it:

Rearrange the equation to get 0 on one side:

It can't be factorised, so use the quadratic formula to get:

OR
10. Re: GCSE Question
(Original post by usycool1)
I'll post a different example and you guys can try the original question on your own

Spoiler:
Show

Multiply everything by (x+7)(x+4):

Simplify it:

Rearrange the equation to get 0 on one side:

It can't be factorised, so use the quadratic formula to get:

OR
thanks i think i've got it. 0.95 and -1.70
Useful resources

## Articles:

Study Help rules and posting guidelinesStudy Help Member of the Month nominations

## Groups associated with this forum:

View associated groups