Question

Tentukan hp dari spldv berikut. Log x^3 - log y = 7 dan log 1/x^2 + log y^5 = -9

Answer 1

Set log x = a --> x = 10^a
log y = b------> y = 10^b
.
3 log x - log y = 7 --> 3a - b = 7
log x^-2 + 5 log y = -9 --> -2a + 5b = -9
..
3a - b = 7.........kali (-2)
-2a + 5b = -9...kali 3
..
-6a + 2b = - 14
-6a +15b = -27
kurangkan
-13b =  13 ---> b = - 1 ---> y = 10^-1 = 1/10
3a -b = 7 --> 3a  = 7+b --> 3a =7-1= 6
a= 2 --> x = 10^2 = 100
.
x = 100, dan y = 1/10 = 0,1