Răspuns :
Răspuns:
a)
1.
[tex]256 = {2}^{8} = > k = 8[/tex]
2.
[tex] \frac{1}{128} = \frac{1}{ {2}^{7} } = {2}^{ - 7} = > k = - 7[/tex]
b)
1.
[tex] \frac{1}{15625} = \frac{1}{ {5}^{6} } = {5}^{ - 6} = > k = - 6[/tex]
2.
[tex]125 = {5}^{3} = > k = 3[/tex]
c)
1.
[tex]27 = {3}^{3} = > k = 3[/tex]
2.
[tex]243 = {3}^{5} = > k = 5[/tex]
Notă: "^" = ridicat la puterea (ex: 2^x = 2 ridicat la puterea x)
a) a = 2^x
1. a = 256 => 256 = 2^x => 2^8 = 2^x => x = 8
2. a = 1/ 128 => 1/128 = 2^x => (128)^(-1) = 2^x => (2^7)^(-1) = 2^x => 2^(-7) = 2^x => x = -7
b) b = 5^x
1. b = 1/ 625 => 1/625 = 5^x => (625)^(-1) = 5^x => (5^4)^(-1) = 5^x => 5^(-4) = 5^x => x = -4
2. b = 125 => 125 = 5^x => 5^3 => x = 3
c) c = 3^x
1. c = 27 => 27 = 3^x => 3^3 = 3^x => x = 3
c = 243 => 243 = 3^x => 3^5 = 3^x => x = 5