Answer:
x=(log(5/4))/(log(4))
Step-by-step explanation:
4^(2x + 1) + 7*4^x - 15 = 0
Let a = 4^x, then we have:
4a^2 + 7a - 15 = 0
<=>4a^2 + 12a - 5a - 15 = 0
<=> 4a(a + 3) - 5(a + 3) = 0
<=>(4a - 5)(x + 3) = 0
<=> a =5/4 (a = -3: invalid)
=> 4^x = 5/4
=> x = log(5/4)/log4
Hope this helps!
:)
