Respuesta :

we are given

[tex]log_0._8(x+4)>log_0._4(x+4)[/tex]

We can use base change formula

[tex]log_a(b)=\frac{ln(b)}{ln(a)}[/tex]

so, we get

[tex]\frac{ln(x+4)}{ln(0.8)} >\frac{ln(x+4}{ln(0.4)}[/tex]

we can move right side term to left side

[tex]\frac{ln(x+4)}{ln(0.8)} -\frac{ln(x+4)}{ln(0.4)}>0[/tex]

[tex]ln(x+4)(\frac{1}{ln(0.8)} -\frac{1}{ln(0.4)})>0[/tex]

we know that

[tex](\frac{1}{ln(0.8)} -\frac{1}{ln(0.4)})<0[/tex]

so, other term should also be less than 0

then only it can be positive or greater than 0

[tex]ln(x+4)<0[/tex]

Let's assume it is equal

[tex]ln(x+4)=0[/tex]

take exponent both sides

[tex]e^{ln(x+4)}=e^0[/tex]

[tex]x+4=1[/tex]

[tex]x=-3[/tex]

and ln(x+4) is also undefined at x+4=0

x=-4

now, we can draw a number line and locate this value

so, we get

[tex]-4<x<-3[/tex]...........Answer

Ver imagen rejkjavik

Answer:

-4 < x < -3

Step-by-step explanation:

Rearranging the equation:

log0.8 (x+4) - log0.4 (x+4) > 0

After changing the base of the logarithms:

ln (x+4)/ln (0.8) - ln (x+4)/ln (0.4) > 0  

ln (x+4) * [1/ln (0.8) - 1/ln (0.4)] > 0

The term [1/ln (0.8) - 1/ln (0.4)] is negative, then:

ln (x+4) < 0

x + 4 < 1

x < -3

We know that the domain of a logarithm are all the positive real numbers, then:

x + 4 > 0

x > -4