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IGCSE MATHS DOUBTS HERE !!!!

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Amii:
By the method of completing the square

x2-6x + 10
=(x-3)2 -32 +10
=(x-3)2 +1

hence p=3 and q =1

SauD~:

--- Quote from: Amii on January 21, 2011, 12:00:07 pm ---By the method of completing the square

x2-6x + 10
=(x-3)2 -32 +10
=(x-3)2 +1

hence p=3 and q =1

--- End quote ---
where did 6x turned it only 3 ???
help! can you explain :(

Amii:

--- Quote from: SimoN on January 21, 2011, 12:09:37 pm ---where did 6x turned it only 3 ???
help! can you explain :(

--- End quote ---
That's the way you half it  :D

x2-ax+b
=(x-1/2a)2 - (1/2a)2 + b

x2+ax+b
=(x+1/2a)2 - (1/2a)2 + b

You want me to give you some example questions to solve?

Arthur Bon Zavi:

--- Quote from: SimoN on January 21, 2011, 12:09:37 pm ---where did 6x turned it only 3 ???
help! can you explain :(

--- End quote ---

There's one formula to solve these type of sums, but will be covered in AS Levels (Pure Mathematics 1)

Equation will be in the form x2 + bx + c = 0

(x + 1/2b)2 = x2 + bx + 1/4b2, so x2 + bx  = (x + 1/2 b)2 - 1/4b2

Adding c to both the sides will give :

x2 + bx+ c = (x2 + bx) + c = { (x + 1/2b)2 - 1/4b2 } + c

I do this way :

x2-6x + 10
(x2 - 6x + 9 + 1)
(x - 3)2 + 1

Therefore, p=3 and q = 1

SauD~:
i know i got some simple and stupid,
but where did the x go, we can't just remove the x as we don't know the value :-[

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