(根号2+根号3+根号5)*(3根号2+2根号3-根号30)最好用文字表述.符号我看不懂

问题描述:

(根号2+根号3+根号5)*(3根号2+2根号3-根号30)最好用文字表述.符号我看不懂

(根号2+根号3+根号5)*(3根号2+2根号3-根号30)
=3*(根号2)的平方+2根号2*根号3-根号2*根号30+根号3*3根号2+根号3*2根号3
-根号3*根号30+根号5*(3根号2+2根号3)-根号5*根号30
=6+2根号6-2根号15+3根号6+6-3根号10+3根号10+2根号15-5根号6
=12

就按死办法算就可以求解。
一项一项×进去
根号2*(3根号2+2根号3-根号30)+根号3*(3根号2+2根号3-根号30)+根号5*(3根号2+2根号3-根号30)
=根号2×3根号2+根号2×2根号3-根号2×根号30+根号3×3根号2+根号3×2根号3-根号3×根号30+根号5×3根号2+根号5×2根号3-根号5×根号30
=6+2根号6-2根号15+3根号6+6-3根号10+3根号10+2根号15-5根号6
=12

(根号2+根号3+根号5)*(3根号2+2根号3-根号30)=(根号2+根号3+根号5)*(根号2+根号3-根号5)*(根号2*根号3)=[(根号2+根号3)²-5]*(根号2*根号3)=2*(根号2*根号3)*(根号2*根号3)
=2*2*3=12.