Mister Exam

Other calculators

log8(x-9)<1/3 inequation

A inequation with variable

The solution

You have entered [src]
log(x - 9)      
---------- < 1/3
  log(8)        
$$\frac{\log{\left(x - 9 \right)}}{\log{\left(8 \right)}} < \frac{1}{3}$$
log(x - 9)/log(8) < 1/3
Detail solution
Given the inequality:
$$\frac{\log{\left(x - 9 \right)}}{\log{\left(8 \right)}} < \frac{1}{3}$$
To solve this inequality, we must first solve the corresponding equation:
$$\frac{\log{\left(x - 9 \right)}}{\log{\left(8 \right)}} = \frac{1}{3}$$
Solve:
Given the equation
$$\frac{\log{\left(x - 9 \right)}}{\log{\left(8 \right)}} = \frac{1}{3}$$
$$\frac{\log{\left(x - 9 \right)}}{\log{\left(8 \right)}} = \frac{1}{3}$$
Let's divide both parts of the equation by the multiplier of log =1/log(8)
$$\log{\left(x - 9 \right)} = \frac{\log{\left(8 \right)}}{3}$$
This equation is of the form:
log(v)=p

By definition log
v=e^p

then
$$x - 9 = e^{\frac{1}{3 \frac{1}{\log{\left(8 \right)}}}}$$
simplify
$$x - 9 = 2$$
$$x = 11$$
$$x_{1} = 11$$
$$x_{1} = 11$$
This roots
$$x_{1} = 11$$
is the points with change the sign of the inequality expression.
First define with the sign to the leftmost point:
$$x_{0} < x_{1}$$
For example, let's take the point
$$x_{0} = x_{1} - \frac{1}{10}$$
=
$$- \frac{1}{10} + 11$$
=
$$\frac{109}{10}$$
substitute to the expression
$$\frac{\log{\left(x - 9 \right)}}{\log{\left(8 \right)}} < \frac{1}{3}$$
$$\frac{\log{\left(-9 + \frac{109}{10} \right)}}{\log{\left(8 \right)}} < \frac{1}{3}$$
   /19\      
log|--|      
   \10/ < 1/3
-------      
 log(8)      

the solution of our inequality is:
$$x < 11$$
 _____          
      \    
-------ο-------
       x1
Solving inequality on a graph