Math Is Fun Forum

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Solving Equations

I have written a general page on Solving Equations

Feedback welcome ... please

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Solving Equations

Hi MathsisFun;

Good page. Helped me a lot with the geometric representation.

Those 3 basic forms

(a+b)(a+b)
(a-b)(a-b)
(a+b)(a-b)

are also the basis for mental arithmetic. Lets take your example:

If you wanted to multiply 38 * 42 you could use that form with y=10.
Answer 16*100 - 4 = 1596 like magic.

For 63 * 57

63*57 = 36 * 100 -9 = 3591

With a little practice and algebra, you can do lots of arithmetic in your head.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.