1.计算: (1)2-(√20+√5)/√5; 解:原式=2-(2√5+√5)/√5 =2-3√5/√5 =2-3 =-1 (2)(3+√2)(3-√2)+3√1/6; 解:原式=9-2+3×√6/6 =7+√6/2 2.计算题 (1)(3√5)2﹣(2﹣3√5)(2+3√5); 解:原式=9+6√5+5-(4-45) =9+6√5-(-41) =9+6√5+5+41 =55+6√5 (2)(√12-2√1/3+√48)÷(2√3); 解:原式=(2√3-2√3/3+4√3)÷(2√3) =16√3/3÷2√3 =8/3 3.计算: (1)(√75-√3)/√3-(√1/5)×(√20); 解:原式=5√3-√3/√3-√4 =4√3/√3-2 =4-2 =2 (2)(√2+1)2-(√3+1)(√3-1); 解:原式=2+2√2+1-(3-1) =2+2√2+1-2 =2√2+1 4.计算: (1)3√3-√8+√2-√27; 解:原式=3√3-2√2+√2-3√3 =-√2 (2)√5(√5-2√2)-(√5-√2)2; 解:原式=5-2√10-(5+2-2√10) =5-2√10-7+2√10 =-2 5.计算题 (1)√3×√6/√2+³√-8; 解:原式=√3×√6/√2+³√-8 =3+(-2) =1 (2)(3+√2)(3-√2)-√12+√27/√3; 解:原式=9-2-(2+3) =7-5=2 6.计算: (1)2√12+3√1-√2×√6; 解:原式=4√3+2√3-2√3=4√3 (2)√48÷√3+|1-√3|-√8-√6/√2; 解:原式=√48÷3+√3-1-(√8/2-√6/2) =4+√3-1-2√3 =1+2√3