Congratulations to Fok Chi Kwong from Yuen Long Merchants Association Secondary School, Hong Kong on this solution.

We may find the required polynomial by starting from the expression :

x=1+2+3. Squaring both sides and simplifying, we get
x-1=2+3


x2 -2x+1=5+26


x2 -2x-4=26


( x2 -2x-4 )2 =24


x4 -4 x3 +4 x2 -8 x2 +16x+16=24


x4 -4 x3 -4 x2 +16x-8=0

Thus p(x) = x4 - 4x3 - 4x2 + 16x - 8 is the required polynomial.

Tony Cardell, State College Area High School, PA, USA, also sent in a good solution.