jawab ya,pkai cranya #matematika minat

17.]
[tex] 5^x + 5^{-x} \geq \frac{26}{5} \\
5^x + \frac{1}{5^x} - \frac{26}{5} \geq 0 \\
Misal \ 5^x = a \\
a + \frac{1}{a} - \frac{26}{5} \geq 0 [ kalikan \ 5a] \\
5 a^2 - 26 a + 5 \geq 0 \\
(5 a - 1)(a - 5) \geq 0 [/tex]

Titik Kritis :
5a - 1 = 0
a = 1/5
5ˣ = 1/5
x = -1

a - 5 = 0
a = 5
5ˣ = 5
x = 1

Diminta yang ≥ 0 , maka
HP : {x | x ≤ -1 atau x ≥ 1}

18.]
²log √27 • ⁹log 16 + ²⁵log 125
[tex] = ^2 \log 3^{\frac32} \cdot ^{3^2} \log 2^4 + ^{5^2} \log 5^3 [/tex]
= ³/₂ • 2 • ²log 3 • ³log 2 + ³/₂ • ⁵log 5
= 3 + ³/₂
= 9/2