the answer is B=1.

solve the quad equation.
when you solved the quad eq. you got two roots.
the root is 1 and -0.5 .

substitute both roots into the 4B^3=3B+1 .

you will find the answer is 1 because B=1 fits with the equation.

This post has been edited by medwolf: Dec 22 2012, 09:34 PM

trials is important because it is needed if u want to make semakan semula for real spm.

based on my theory,
i think the real spm also based on trial results.
let say there is a lot of student got 'B+' and less 'A-'.
so they need to increase the number of ppl getting 'A' .
so they will look at ur trial result and school.
thats why elite school always got many ppl with 'A'.