I know the answer = 2 + √2
but it didn't work out when i tried to calculate it
i did it by equating coefficents
20 + 14√2 = (d + e √2)^3
I expanded the brackets and equate coefficients with and without √2, and got these 2 equations
d^3 + 6de^2 = 20
2e^3 + 3ed^2 = 14
and I am having major difficulty in solving them
the equations are correct, by substituting d = 2 and e = 1
So the problem is, how to solve these 2 equations, i tried the substitution method and it got up to a polynomial of d or e to the power of 9, which is a cubic equation of (d or e) cube, and i know it can be solved by the way of solving cubic equations, but this seems to be too much of a trouble for an answer of 1 and 2, so, the question is...... does anyone have a better insight in solving those equations
Help us out please! Thank you very much!
2007-08-05
00:44:58
·
3 answers
·
asked by
kwanylongy
2
in
Mathematics