tolong jawabannya dan caranya yah besok dikumpul no 12

Kelas 9 Matematika
Bab Akar dan Bangun Ruang

1/(2 - √2)
= (1/(2 - √2)) . (2 + √2)/(2 + √2)
= (2 + √2)/(2² - √2²)
= (2 + √2)/(4 - 2)
= (2 + √2)/2

Luas permukaan kubus
= 6 . s²
= 6 . ((2 + √2)/2)²
= 6 . (2² + 4 √2 + √2²)/4
= 6 . (4 + 4√2 + 2)/4
= (36 + 24√2)/4
= (9 + 6√2) cm²

✩✩ D ✩✩