A(n)=a(1)+d(n-1)
a(23)= a(1)+d(23-1)
a(1)=-15
d=3
подставляем:
a(23)=-15+3*22
a(23)= -15+66
<u>a(23)=51</u>
2х-17-4х=63 2х-17-4х-63=0 2х-4х=63+17 -2х=80 х=-40
......................................
(5^2+3)•5^2х-1
(25+3)•5^2х-1
28•5^2х-1
5cos57/sin33
cos меняем на sin (90-57)=sin33
5sin33/sin33 = 5