Jika x dan y memenuhi 2logx^2 + 3log1/y^3 = 4 dan 2logx + 3logy^4=13, maka 4logx - ylog9 =

²logx² +³logy⁻³ =4
⇒2²logx -3³logy =4

misal ²logx=p, ³logy=q
maka, 2p-3q=4.... (1)

²logx + ³logy⁴=13
⇒²logx + 4³logy=13
⇒p+4q=13...(2)

subtitusikan pers.1 &2
2p-3q=4
2p+8q=26

diperoleh
p=5 ⇒ ²logx=5
q=2 ⇒ ³logy=2
⇒
⁴logx - [tex]^{y} [/tex]log9 = 
[tex] ^{4}log x- \frac{1}{ 3^{2}logy} [/tex]
[tex] \frac{1}{2} ^{2}log x- \frac{2}{ ^3logy}[/tex]
[tex]\frac{5}{2}- \frac{2}{ 2} = \frac{3}{2} [/tex]

jika salah koreksi yaa.. hehe