Flag Algebra> LOGARITHMIC QUESTION...
question mark

1. LOG(x-1)(base 4) = LOG(x-3)(base 2) solution for 'x'

2. if logx(base 8) + log(x-4)(base 8) +log(x-6)(base 8) =2then x= ?

saumya shivhare

saumya shivhare , 15 Years ago
Grade 11
anser 2 Answers
Aniket Patra

Ans 1 is most probably 2 and 5.

Last Activity: 15 Years ago
palash ahuja

ist question solution is here 

log(x-1)base4 = 1/2 log(x-1)(base2)

therefore 

1/2log(x-1)base2 = log(x-3)(base2)

therefore 

log(x-1)base2 = 2log(x-3)base2 = log(x-3)^2(base2)

since both sides have the same base therefore we can remove the log 

we get

(x-1)=(x-3)^2 = x^2 - 6x +9

on solving further we get

x^2-7x+10=0

x^2-2x-5x+10=0

x(x-2) -5(x-2)=0

(x-5)(x-2)=0

or x=5 or x=2 

 

iind solution is here

logx(base8)+log(x-4)base8+log(x-6)base8=2

then 

log x(x-4)(x-6)(base8)=2

or 

x(x-4)(x-6)=64

on solving we get a cubic equation

x^3 -10x^2 +24x - 64=0

let the roots of the given eq. be a,b and c

then a + b+c= 10

& abc = 64

now by a.m.-g.m. inequality we get

(a+b+c)> Or = 3(abc)^1/3 = 3*4 = 12

which is less than a+b+c 

hence no solutions are possible 

i hope you have understood the solutions 

PALASH AHUJA 

 

ApprovedApproved
Last Activity: 15 Years ago
star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments