Вложение -----------------------------------------------
10^x = t > 0
t^2 - 2t - 80 = 0
t1 = 10; t2 <0
10^x = 10
x = 1
1) 8^5 • 0,2^ - 7 = 2^15 • 5 ^ 7 = ( 10 ^ 7 ) • ( 2 ^ 8
2) ( 10^7 )•( 2^8 ) : ( 10^15 ) = 2^8 : 10^8 = ( 2/10 )^8 = ( 1/5 ) ^8 = 5 ^ ( - 8 )