A few days ago
Can someone please help solve : 4^x – 7(2)^x – 8 = 0 ?
It’s something to do with Indices and Logarithms. Help find the value of x.
Top 2 Answers
A few days ago
Favorite Answer
This is quite complex but here it is.
4^x can be rewritten as 2^(2x)
Let’s 2^x = a
then 4^x can now be written as a^2
The entire thing now will be:
a^2 – 7a – 8 = 0 –> quadratic equation
Let’s factor
(a – 8)(a + 1) = 0
a = 8 or a = -1
Since we defined a to be 2^x, then
2^x = 8 or (2^x = -1) <--- discard because it's undefined 2^x = 2^3 x therefore is 3. The final answer is 3.
0
A few days ago
You cant use the Quadratic formula….so the answer is 0.
0
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