Question 15
Both $a$ and $\sqrt{23-8\sqrt7}+a\sqrt{23+8\sqrt7}$ are rational. Find $a$.
HKIMO 2026 THPT (Grades 10–12 shared) National Final (Heat) Set 05 Question 15
HKIMO · HKIMO 2026 THPT (Grades 10–12 shared) National Final (Heat) Set 05
HKIMO · HKIMO 2026 THPT (Grades 10–12 shared) National Final (Heat) Set 05