5 akar 2-4 per 7 akar 2+4

(5√2 - 4) / (7√2 + 4)
= (5√2 - 4) / (7√2 + 4) × (7√2 - 4) / (7√2 - 4)
= (5√2 - 4)(7√2 - 4) / (7√2 + 4)(7√2 - 4)
= (35√4 - 20√2 - 28√2 + 16) / (49√4 - 16)
= (70 - 48√2 + 16) / (98 - 16)
= (86 - 48√2) / (82)
= (44 - 24√2) / (41)



semoga membantu ^_^