tolong bantu di jawab

[(2 akar 7) + (4 akar 5)] [(5 akar 7) - (akar 5)]
= 10.7 - (2 kar 7 akar 5) + (20 akar 7 akar 5) - 4.5
= 70 + 18 akar 7 akar 5 - 20
= 50 + 18 akar 35
B