Saling bantu aja gan, tolong bantu yak,

a²b = (√2 + √3)² × (5 - 2√6)
= (2 + 2√6 + 3) × (5 - 2√6)
= (5 + 2√6) × (5 - 2√6)
= 25 - 24 = 1

Maaf kalo slh trims :)