Question

Following e.g. C, how do you do D? 30 points

Answer 1

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!

:)

Answer 2

x=(log(5/4))/(log(4))

Explanation: