Friday, December 07, 2007

Solve this

My cousin-in-law, Jek Kin has started a new blog on Mathematics. He was formerly a maths teacher in a secondary school in Sungai Petani.

Thought of posting an interesting math question I've seen many years ago. The solution is quite easy, but only if you can figure out how to start.



Feel free to attempt and post your solutions (or describe it) here.

Good luck!

3 comments:

Anonymous said...

Let the answer be x.
sqrt(12+x) = x
x^2 -x-12 =0
(x+4)(x-3)=0
Since x can't be -ve, x=3

Not sure whether that's the solution. Just guessing :)

Jih Ying 致颖 said...

The method is correct but the answer is 4. I think you've made a careless mistake in the final step. It should be (x-4)(x+3) = 0. Well done!

Anonymous said...

oya hor.so careless...hahaha :p