1. 2+√5 -------- = 2√5 2. 4+√2 -------- = 4-√2

Bab Bilangan Irrasional
Matematika SMP Kelas IX

1] ( 2 + √5 ) / (2√5)
= (2 + √5) . (2√5) / (2 √5)²
= (4 √5 + 20) / (2² . √5² )
= (4 √5 + 20) / (4 . 5)
= (√5 + 5)/5
= (1/5) √5 + 1

2] (4 + √2) / (4 - √2)
= (4 + √2) (4 + √2) / (4² - √2²)
= (4² + 2 . 4 √2 + √2²) / (16 - 2)
= (16 + 8√2 + 2) / 14
= (18 + 8√2) / 14
= (9 + 4√2)/7