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With a quadratic equation that can be factorised is it true to say that a times b = c? Is it really that simple?

2006-07-26 22:46:28 · 6 answers · asked by Anonymous in Science & Mathematics Mathematics

6 answers

I don't know.

Let's find out.

How about we start with a factorised equation already and then put it into the form aX^2 + bX + c = 0

let's start with
0 = l.(x + m) (x + n) where l, m and n are just some variables

= l. (x^2 + (m+n)x + mn)

= lX^2 + l(m+n)x + lmn

which is of the form aX^2 + bX + c

does c = a x b?

l x l(m+n) = l^2m + l^2n

I think you are going to find that this does not = lmn all the time

Perhaps you could take it further and discover for what values of l, m and n the equation IS true?

lmn = l^2m + l^2n

when l or (m+n) = 0, for instance...
and any other times?

2006-07-26 22:54:34 · answer #1 · answered by Orinoco 7 · 0 2

Absolutely not. For instance, take the quadratic equation x²-2x+1=0. In this case, a=1, b=-2, and c=1. a*b≠c, but this equation trivially factors into (x-1)(x-1).

2006-07-27 06:01:45 · answer #2 · answered by Pascal 7 · 0 0

Yes

2006-07-27 05:50:42 · answer #3 · answered by female_lizzzzzard 3 · 0 0

ab = c is only true for specialized (custom) quadratics. However, it is not true for every factorizable quadratic.

E.g.
2x² + 5x + 3 = 0
can be factorized as
(2x + 3)(x + 1) = 0

but
ab = 2(5) = 10
c = 3

Therefore, ab is not equal to c.

^_^

2006-07-27 06:47:14 · answer #4 · answered by kevin! 5 · 0 0

Possibly with the odd equation it might work, but not every time.

2006-07-27 06:11:09 · answer #5 · answered by Brenmore 5 · 0 0

yes

2006-07-27 05:54:37 · answer #6 · answered by Inquistive_man 3 · 0 0

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