Examples with solutions for Rules of Logarithms Combined: Using variables

Exercise #1

log23x×log58=log5a+log52a \log_23x\times\log_58=\log_5a+\log_52a

Given a>0 , express X by a

Video Solution

Step-by-Step Solution

Answer

2a2273 \sqrt[3]{\frac{2a^2}{27}}

Exercise #2

xln7= x\ln7=

Video Solution

Answer

ln7x \ln7^x

Exercise #3

log89alog83a= \frac{\log_89a}{\log_83a}=

Video Solution

Answer

log3a9a \log_{3a}9a

Exercise #4

log4x9log4xa= \frac{\log_{4x}9}{\log_{4x}a}=

Video Solution

Answer

loga9 \log_a9

Exercise #5

(log7x)1= (\log_7x)^{-1}=

Video Solution

Answer

logx7 \log_x7

Exercise #6

Solve for X:

log3(x+2)log29=4 \log_3(x+2)\cdot\log_29=4

Video Solution

Answer

2 2

Exercise #7

4a2log79 ⁣:log97=16 \frac{4a^2}{\log_79}\colon\log_97=16

Calculate a.

Video Solution

Answer

±2 \pm2

Exercise #8

2xlog89log98= \frac{\frac{2x}{\log_89}}{\log_98}=

Video Solution

Answer

2x 2x

Exercise #9

ln4x= \ln4x=

Video Solution

Answer

log74xlog7e \frac{\log_74x}{\log_7e}

Exercise #10

nlogxa= n\log_xa=

Video Solution

Answer

logxan \log_xa^n

Exercise #11

xlogm13x= x\log_m\frac{1}{3^x}=

Video Solution

Answer

x2logm3 -x^2\log_m3

Exercise #12

Find X

log84x+log8(x+2)log83=3 \frac{\log_84x+\log_8(x+2)}{\log_83}=3

Video Solution

Answer

1+312 -1+\frac{\sqrt{31}}{2}

Exercise #13

2log(x+1)=log(2x2+8x) 2\log(x+1)=\log(2x^2+8x)

x=? x=\text{?}

Video Solution

Answer

3+10 -3+\sqrt{10}

Exercise #14

Calculate X:

2log(x+4)=1 2\log(x+4)=1

Video Solution

Answer

4+10 -4+\sqrt{10}

Exercise #15

log4(x2+8x+1)log48=2 \frac{\log_4(x^2+8x+1)}{\log_48}=2

x=? x=\text{?}

Video Solution

Answer

4±79 -4\pm\sqrt{79}

Exercise #16

2log7(x+1)log7e=ln(3x2+1) \frac{2\log_7(x+1)}{\log_7e}=\ln(3x^2+1)

x=? x=\text{?}

Video Solution

Answer

1,0 1,0

Exercise #17

12log3(x4)=log3(3x2+5x+1) \frac{1}{2}\log_3(x^4)=\log_3(3x^2+5x+1)

x=? x=\text{?}

Video Solution

Answer

54±174 -\frac{5}{4}\pm\frac{\sqrt{17}}{4}

Exercise #18

x=? x=\text{?}

log125log124log12xlog123 \log_{\frac{1}{2}}5-\log_{\frac{1}{2}}4\le\log_{\frac{1}{2}}x-\log_{\frac{1}{2}}3

Video Solution

Answer

0 < x\le3.75

Exercise #19

log35x×log179log174 \log_35x\times\log_{\frac{1}{7}}9\ge\log_{\frac{1}{7}}4

Video Solution

Answer

0 < x\le\frac{1}{245}

Exercise #20

What is the domain of X so that the following is satisfied:

\frac{\log_{\frac{1}{8}}2x}{\log_{\frac{1}{8}}4}<\log_4(5x-2)

Video Solution

Answer

\frac{2}{3} < x