a)(√3+2√2)²-4√6;

(√3+2√2)² = (√3+2√2)(√3+2√2)
Expanding using FOIL method:
= √3√3 + √3(2√2) + 2√2√3 + 2√2(2√2)
= 3 + 2√6 + 2√6 + 4√2
= 3 + 4√6 + 4√2

Now, subtracting 4√6 from the result above:
= 3 + 4√6 + 4√2 - 4√6
= 3 + 4√2

So, (√3+2√2)² - 4√6 = 3 + 4√2.