8^9 ·4^5 = (2³)^9·(2²)^5 = 2^27·2^10 = 2^(27+10) =2^37
(2^5)·(2^4)^6·(2^6)³ = 2^5·2^24·2^18 = 2^47
Sn=(2a1+(n-1)•d)•n /2 =300
a1=3, d=7-3=4
(2•3+4•(n-1))•n/ 2=300
(6+4n-4)•n=300•2
4n^2+2n-600=0
2n^2+n-300=0
n1=
n2=
n натуральное число
Sn=( a1+x)•n /2=300
(3+x)•n=600
3+x=600:n
x=600:n-3