07-16-2015, 10:30 AM
8^(3+6x) = 4
the key here is to recognize that
8 and 4 are both powers of 2
now go here
https://www.mathsisfun.com/algebra/exponent-laws.html
scroll down to the section named
------
Laws of Exponents
Here are the Laws (explanations follow):
-----
now study the chart
see the row that says
(x^m)^n = x^mn
so
8^(3+6x) = 4
is the same as
(2^(3))^(3+6x) = 2^2
yes, that line is confusing
so look at it again
because now we're going to use the law we just learned and rewrite that line so it becomes
2^(3*(3+6x)) = 2^2
now the bases are the same
so it's basically
2^something = 2^of something else
so
something = something else
so
(3*(3+6x)) = 2
so
9 + 18x = 2
18x = -7
x = -7/18
x = -0.389
but the entire point of this problem is is to recognize that
8 and 4 are both powers of 2
and to know that law of exponents
the key here is to recognize that
8 and 4 are both powers of 2
now go here
https://www.mathsisfun.com/algebra/exponent-laws.html
scroll down to the section named
------
Laws of Exponents
Here are the Laws (explanations follow):
-----
now study the chart
see the row that says
(x^m)^n = x^mn
so
8^(3+6x) = 4
is the same as
(2^(3))^(3+6x) = 2^2
yes, that line is confusing
so look at it again
because now we're going to use the law we just learned and rewrite that line so it becomes
2^(3*(3+6x)) = 2^2
now the bases are the same
so it's basically
2^something = 2^of something else
so
something = something else
so
(3*(3+6x)) = 2
so
9 + 18x = 2
18x = -7
x = -7/18
x = -0.389
but the entire point of this problem is is to recognize that
8 and 4 are both powers of 2
and to know that law of exponents