Question

Решите:$5^{x}-6* 5^{-x} =3,8$

Answer 1

( 5 ^ X ) - 6 * ( 5 ^ - X ) = 3,8 ; 5 ^ X = A ; A > 0 ; A - ( 6 / A ) = 19/5 ; A не равен нулю ; 5A^2 - 30 = 19A ; 5A^2 - 19A - 30 = 0 ; D = 361 + 600 = 961 ; V D = 31 ; A1 = ( 19 + 31 ) : 10 = 5 ; A2 = ( 19 - 31 ) : 10 = - 1,2 ( < 0 ) ; 5 ^ X = 5 ; X = 1 Ответ Х = 1