a couple of maths questions...help needed (1 Viewer)

tabsheer

New Member
Joined
Aug 18, 2008
Messages
10
Gender
Male
HSC
2010
heyy guyz

need help doin a couple of questions from a past paper in my school
can any1 plz solve these with showing workin so i get how to do it coz im really confused and it doesnt work out wenever i try


  1. Solve t = ½ square root a/L for L
  2. Factorise: a) 2x² -3x -4
b) x² + 5x + 10

Thanx in advance



 

M@ster P

Member
Joined
Feb 9, 2008
Messages
619
Gender
Male
HSC
2009
For Question 2a and 2b you use the quadratic formula
 

Drongoski

Well-Known Member
Joined
Feb 22, 2009
Messages
4,255
Gender
Male
HSC
N/A
Q1: don't understand question

Q2: are you sure questions correct ?
 
Last edited:

tabsheer

New Member
Joined
Aug 18, 2008
Messages
10
Gender
Male
HSC
2010
i dont understand Q 1 either =S it was written like that


yeah question 2 is correct i tried and it didnt come -_- ...cnt use quadratic formula coz its factorising not finding x
 

Drongoski

Well-Known Member
Joined
Feb 22, 2009
Messages
4,255
Gender
Male
HSC
N/A
Where do you get these questions from? Q2 can't be done.
 

undalay

Active Member
Joined
Dec 14, 2006
Messages
1,002
Location
Ashfield
Gender
Male
HSC
2008
i dont understand Q 1 either =S it was written like that


yeah question 2 is correct i tried and it didnt come -_- ...cnt use quadratic formula coz its factorising not finding x
You can use quadratic formula to factorise.

and then u get
x=a,b

then factors would then just be (x-a)(x-b)
 

addikaye03

The A-Team
Joined
Nov 16, 2006
Messages
1,267
Location
Albury-Wodonga, NSW
Gender
Male
HSC
2008
heyy guyz

need help doin a couple of questions from a past paper in my school
can any1 plz solve these with showing workin so i get how to do it coz im really confused and it doesnt work out wenever i try


  1. Solve t = ½ square root a/L for L
  2. Factorise: a) 2x² -3x -4
b) x² + 5x + 10

Thanx in advance



a)

t=1/2rt(a/L)

2t=rt(a/L)

4t^2=a/L

L=a/4t^2

2b)

x^2+5x+10

(x+5/2)^2-15/4

[(x+5)-rt15/4][(x+5)+rt15/4]

Are they right... those Q are just fucking stupid.
 
Last edited:

Timothy.Siu

Prophet 9
Joined
Aug 6, 2008
Messages
3,449
Location
Sydney
Gender
Male
HSC
2009
You can use quadratic formula to factorise.

and then u get
x=a,b

then factors would then just be (x-a)(x-b)
u cant do that for the first one, well u can but u cud get it wrong

Factorise: a) 2x² -3x -4
2(x^2-3/2x-2)=2(x-3/4)^2-17/4=2(x-3/4+root17/2)(x-3/4-root17/2)
b) x² + 5x + 10
no solution
 
Last edited:

GUSSSSSSSSSSSSS

Active Member
Joined
Aug 20, 2008
Messages
1,102
Location
Turra
Gender
Male
HSC
2009
yea lookin at ur graduation year....q2b has no solutions and so cannot be factorised
 

Drongoski

Well-Known Member
Joined
Feb 22, 2009
Messages
4,255
Gender
Male
HSC
N/A
Hey GUS13.

You may find my posting under "Which one do you prefer .. " more interesting ? than dealing with these problems.
 
Last edited:

shell.q

Member
Joined
May 8, 2008
Messages
186
Gender
Female
HSC
2009
1. as stated above
t=1/2rt(a/L)

2t=rt(a/L)

4t^2=a/L

L=a/4t^2

2a. 2(x^2-3x-4) 2(x+1)(x-4)
i.e x = -1, 4
thts how i would do tht

b. this is where i would use the quadratic formula
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top