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I went by a slightly different method.
I first took cube root on both sides, giving me 2^m=3
then I squared both sides, which gives 2^2m=9 or 4^m=9!!!
easy!!
woahh!!..i did this w/out solution ... analyzing the problem when you dont know it can improve your brain...
Nice solution, this is the same as how I did it but another method is 4^ IN(3)/(In 2)
I did it same way.
8
m
=
2
7
⇒
(
2
3
)
m
=
2
7
⇒
(
2
m
)
3
=
3
3
⇒
2
m
=
3
⇒
(
2
m
)
2
=
3
2
(Squaring both sides)
⇒
(
2
2
)
m
=
9
⇒
4
m
=
9
8 m = ( 4 × 2 ) m = 4 m × 2 m
4 m × 2 m = 2 7
So, 4 m = 2 m 2 7 .
If: m = l o g 8 2 7
then: 4 m = 2 l o g 8 2 7 2 7 = 3 2 7 = 9 .
Alternatively: 4 m = 4 l o g 8 2 7 = 9
8 m = 2 7 ----> 2 3 m = 3 3
3 m . l n 2 = 3 . l n 3
m . l n 2 = l n 3
2 m = 3
4 m = 2 m . 2 m = 3 x 3 = 9
To find the value of m , we must take the logarithm in base 8 of each side and work from there onwards:
lo g 8 8 m = lo g 8 2 7
Due to the Power Property of logarithms ( lo g b m n = n ( lo g b m ) ) we are able to simplify the left side of the equation:
lo g 8 8 m = m ( lo g 8 8 ) = m ( 1 ) = m
For now, we will express the right side as simply l o g 8 2 7 .
After simplifying this equation, we know that m = lo g 8 2 7 .
The question asks what the value of 4 m is. To find it, we have to plug our value of m back into this expression:
4 ( lo g 8 2 7 ) of which the answer is 9
8 m = 2 7 lo g 8 2 7 = m lo g 2 3 3 3 = m 3 1 ⋅ 3 ⋅ lo g 2 3 = m lo g 2 3 = m 2 m = 3 ( 2 m ) 2 = ( 3 ) 2 2 2 m = 9 ( 2 2 ) m = 9 4 m = 9
Given\quad that\\ \qquad \qquad { 8 }^{ m }={ 27 }\\ Step\quad I\\ \qquad Take\quad cube\quad root\quad on\quad both\quad sides.\\ \qquad \quad \quad { { (8 }^{ m }) }^{ \frac { 1 }{ 3 } }={ 27 }^{ \frac { 1 }{ 3 } }\quad =>\quad { { (2 }^{ 3m }) }^{ \frac { 1 }{ 3 } }={ ({ 3 }^{ 3 }) }^{ \frac { 1 }{ 3 } }\\ or\qquad \boxed { { 2 }^{ m }={ 3 } } \\ Step\quad II\\ \qquad Now\quad take\quad squre\quad on\quad both\quad sides\\ \qquad { { ( }2^{ m }) }^{ 2 }={ 3 }^{ 2 }\\ we\quad get\quad \boxed { { 4 }^{ m }=9 } \\
8 m = ( 2 3 ) m = ( 2 m ) 3 = 2 7 ⇒ 2 m = 3 ⇒ ( 2 m ) 2 = ( 2 2 ) m = 4 m = 9
A fun one!
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This can be written as:
2 3 m = 2 7
Therefore:
( 2 2 m ) 2 3 = 2 7
∴ 2 2 m = 4 m = 2 7 3 2 = 3 2 = 9