210.
1) √(√7 -2)² + √(√7 -5)² =√7 -2 +|√7 -5| =√7 -2 +5 -√7 = 3
2) √(√15 -2)² - √(√15 -3)² = √15 -2 - (√15 -3) = √15 -2 -√15 +3 =1
3) √√(28-16√3) = √√(4*(7-4√3)) =√2√(7-4√3)= √2√(2-√3)² =
=√(2*(2-√3) = √(4-2√3) = √(1-√3)² = |1-√3| = √3 -1
4) √√(68-√4608) =2 -√2
1) √(68-√4608) = √[68+√(68²-4608)] - √[68 - √(68²-4608)] =
[ 2 ] [ 2 ]
= √[(68+4)/2] - √[(68-4)/2] =√36 - √32 = 6 -√32
2) √(6-√32) = √[6+√(6²-32)] - √[6-√(6²-32)] = √[(6+2)/2] - √[(6-2)/2] =
[ 2 ] [ 2 ]
=√4 - √2 = 2 -√2