A)2*5*3.8=38
б)4*2.5*0.061=6.1
в)0.25*4*6.54=6.54
г)0.2*5*13.7=13.7
д)(0.2*5)*(0.25*4)=1
е)1.5*2*2.2=4.4
Sn=0,5*(a1+an)*n;
3069=0,5*(429+an)*n;
6138=(429+an)*n;
an=a1+d(n-1)=429-22n+22=451-22n;
6138=(429+451-22n)*n;
6138=880n-22n^2;
n^2-40n+279=0;
D=1600-1116=484;
n1=(40-22):2=9;
n2=(40+22):2=31;
ответ:9; 31
Нод(35,45)=3*3*5*5=225
35=5*7
45=3*3*5