1) (1+√6)(3-√6)=3-√6+3√6-6= -3+2√6
3) (√7-2)(√7-1)=7-√7-2√7+2=9-3√7
5) (√8-√2)(√2-6)=(2√2-√2)(√2-6)=√2(√2-6)=2-6√2
7) (3√6-4)(3√6-5)=54-15√6-12√6+20=74-27√6
9) (√3+√7)(2√3-√7)=6-√21+2√21-7= -1+√21
11) (1-33)(1+5√3)=1+5√3-3√3-45= -44+2√3
13) (√11-2√3)(√11-3√3)=(√11-2√3)(√11-3√3)=11-3√33-2√33+18=29-5√33