Question

Nomor 1 dan 2 tolong jawab dengan caranya...

Answer 1

Verified answer

^tanda pangkat
1) dijabarin dulu x^(log 1/x) = x^(log x^-1)
= x^(-1.log x) = 1 / x^log x
maka persamaan jadi
x^log x - 10/x^log x - 9 = 0
misal x^log x = p
p - 10/p - 9 = 0
---------------------- × p
p² - 10 - 9p = 0
p² - 9p - 10 = 0
(p + 1)(p - 10) = 0
p = -1 atau p = 10
x^log x = -1 (tidak memenuhi)
x^log x = 10
x^log 10 = log x
x = 10 atau x = 1/10 = 0,1
x1² + x2² = 10² + 0,1² = 100 + 0,01
= 100,01

2) (x²+2x-3)(-x+7)^8 / (x²+x+1) ≥ 0
(x+3)(x-1)(-x+7)^8 / (x²+x+1) ≥ 0
(-x+7)^8 = definit positif
(x²+x+1) = definit positif
buat garis bilangan di x = -3 dan x = 1
+ + + + - - - - - + + +
--------•---------•---------
```````` -3 ````````` 1
x ≤ -3 atau x ≥ 1