(akar 3 + akar 5) (akar 3 - akar 5)

(Akar 3 + akar 5)(akar 3+akar 5)
= (akar 3 × akar 3)+(akar 3 × akar 5)+ (akar 5 × akar 3)+(akar 5 × akar 5)
= 3+akar 15+akar 15+5
= 3+5+akar 15+akar 15
= 8+2 akar 15

Maaf kalo salah