(68,56 - 25,3)/2=43,26/2=21,63=а,
(2,405+ 3,41)*2=5,815*2=11,63=b,
a-b= 21,63- 11,63=10/
Ответ:10.
16/4=4
sqrt-корень
(5-sqrt(2))^2+4(5-sqrt(2))-7=25-10sqrt(2)+2+20-4sqrt(2)-7=40-14sqrt(2)