√72-√288*sin²(21π/8)=√72-√(4*72)*sin²(21π/8)=√72-2√72*sin²(21π/8)=√72*(1-2sin²(21π/8))=√72*cos(2*(21π/8))=√72cos(21π/4)=√72cos(5π+π/4)=√72*(-cos(π/4))=-√72*сos(π/4)=-√72*(√2/2)=-√144/2=-12/2=-6
ответ: -6
А) 8,16,24, 32,40,48, 56, 64, 72, 80 и т.д..
б)11,22,33,44,55,66,77,88,99.
в)48, 96.
г)99.
2400:x=2
x=2400:2=1200
a+21000=100000
a=10000-21000=79000
y*4=560000
y=560000:4=140000
b-47000=100000
b=100000+47000=147000
1)38:2=19мм - половина доски
2)38+19=57мм
Ответ: 57мм длина гвоздя