Question

Помогите!!!!!!!!!!!!!

Answer 1

9 ^ x - 6 * 3 ^ x - 27 = 0
3 ^ x = a ; a > 0
a^2 - 6a - 27 = 0
D = 36 + 108 = 144 = 12^2
a1 = ( 6 + 12 ) : 2 = 9
a2 = ( 6 - 12 ) : 2 = - 3 ( < 0 )
3 ^ x = 9 
3 ^ x = 3 ^ 2 
x = 2 
Ответ 2 
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4 ^ ( 4x - 1 ) + 4 ^ ( 4x - 2 ) + 4 ^ ( 4x - 3 ) = 168 
4 ^ ( 4x - 1 ) * ( 1 + 4 ^ ( - 1 ) + 4 ^ ( - 2 )) = 168 
4 ^ ( 4x - 1 ) * ( 1 + 0,25 + 0,0625 ) = 168 
4 ^ ( 4x - 1 ) = 168 : 1,3125 
4 ^ ( 4x - 1 ) = 128 
4 ^ 4x * 0,25 = 128
4 ^ 4x = 128 : 0,25 
4 ^ 4x = 512
2 ^ 8x = 2 ^ 9 
8x = 9
x = 1,125
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( 7/5 ) ^ ( x + 3 ) ≤ 1 24/25 
( 7/5 ) ^ ( x + 3 ) ≤ 49/25
( 7/5 ) ^ x ≤ ( 7/5 ) ^ 2 
x  ≥ 2 
[ 2 ; + ∞ )

Answer 2

первый решила
надеюсь, всё верно