ask/29406220 ----------------------
1.19 . (√28 - √12) *√(10 +√84) =2(√7- √3)*√(7 +2√7*√3 +3) =2(√7- √3) *√(7 +√3)² = 2(√7- √3) *(7 +√3) =2( (√7)²- (√3)² ) =2(7 -3) =2*4 = 8 .
1.20 . ( (15 / (√6 +1) +4 / (√6 -2) - 12 / (3 -√6) ) *(√6+11 ) = ( (3(√6 -1) +2(√6+2) - 4( 3 +√6 ) ) *(√6+11 )= (3√6 -3 +2√6 +4 -12- 4√6)*(√6+11 ) = (√6 -11)*(√6+11 ) =(√6)² -11² =6 -121 =-115 .
Удачи !