Question

Gente dar uma força que eu esqueci?
a)(1/8)^x=128
b)1/125=625^x
c) 8^x-9=16^x/2
d)0,2^x=(1/125)^x-6
e)7^x=343

Answer 1

a
(1/8)ˣ = 128 = 2⁷
[( 1/2)³ ]ˣ = 2⁷
( 1/2)³ˣ = ( 2 )⁻⁷
( 1/2)³ˣ = ( 1/2)⁷
3x = 7
x = 7/3 ***
b
( 1/125) = 625ˣ
( 1/5)³  =[(1/5)⁴]ˣ
( 1/5)³ = ( 1/5)⁴ˣ
4x = 3
x = 3/4 ****
c
(8)ˣ⁻⁹ = ( 16)ˣ/²
(2³)ˣ⁻⁹ =( 2⁴ )ˣ/²
Notas :
3 . ( x - 9  = 3x - 27
4/1 * x/2 = 4x/2 = 2x 
( 2 )³ˣ⁻²⁷ = ( 2 )²ˣ
3x - 27 = 2x
3x - 2x = 27
x = 27 ***
d
( 2/10)ˣ = ( 1/125)ˣ⁻⁶
( 1/5)ˣ  = [(1/5)³]ˣ⁻⁶
Nota : 3 * ( x - 6)  = 3x - 18 **
( 1/5)ˣ = ( 1/5)³ˣ⁻¹⁸
x = 3x - 18
x - 3x = -18
-2x = - 18
2x = 18
x = 18/2 = 9 ***
e
7ˣ = 343
7ˣ = 7³
x = 3 ***