а)(√2-√5)(√5+2√2)
б)(1+3√2)(3√2-1)
в)(1-2√3)²

a) (√2-√5)(√5+2√2)=√10+4-5-2√10=-√10-1б) (1+3√2)(3√2-1) = 1-18=-17в) (1-2√3)^2=1+12-4√3=13-4√3