tolong kerjain nomer 6 & 9 yaa please :))

6 a. 6√8 + 5 √25 x 8 - 12 √9 x 8 = 6√8 + (5 x 5)√8 - (12 x 3)√8 = 6√8 + 25√8 - 36√8 = (6 + 25 + 36)√8 = -5√8
b. 4(5 - √6)(√3 + √2) = (20 - 4√6)(√3 + √2) = (20 x √3)+(20 x √2)-(4√6 x √3)-(4√6 x √2)
= 20√3 + 20√2 - 4√18 - 4√12