Math Is Fun Forum

Identity

Member

Registered: 2007-04-18

Posts: 934

Miscellaneous Math Marathon

How about a marathon dedicated to any and all non-calculus topics?

Rules:
1. Calculus (limits, derivatives, integration), as well as other absurdly advanced topics (differential geometry, topology etc.) is forbidden. If that's your style you'll have to find another way.
2. Provide working for your solution
3. Post your own problem right after you have solved the previous one.

I'll get started,

Find all roots of x:

Last edited by Identity (2007-09-04 02:09:49)

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,428

Re: Miscellaneous Math Marathon

Let x²-9x=y.
The equation becomes y²-7y+12=0
y=[7± √ (49-48)]/2= (7+1)/2or (7-1)/2=4 or 3.
Putting y=4,
x²-9x=4 or x²-9x-4=0.
x=[9± √(81+16)]/2= (9+  √97)/2 or (9- √97)/2.

Putting y=3,
x²-9x=3or x²-9x-3=0.
x=[9± √(81+12)]/2= (9+√93)/2 or (9-√93)/2.

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