Solve for x?

#4^(2x) - 17(4^(x)) + 16 = 0#

1 Answer
Jul 23, 2017

#x = 0, 2#

Explanation:

We have: #4^(2 x) - 17 (4^(x)) + 16 = 0#

#Rightarrow (4^(x))^(2) - 17 (4^(x)) + 16 = 0#

If you haven't noticed already, this equation is now in the form of a quadratic equation. #4^(x)# can be considered as a variable in this case.

Let's apply the quadratic formula:

#Rightarrow 4^(x) = frac(17 pm sqrt((- 17)^(2) - 4(1)(16)))(2(1))#

#Rightarrow 4^(x) = frac(17 pm sqrt(289 - 64))(2)#

#Rightarrow 4^(x) = frac(17 pm sqrt(225))(2)#

#Rightarrow 4^(x) = frac(17 pm 15)(2)#

#Rightarrow 4^(x) = 1, 16#

Let's solve for #x# for each case:

#Rightarrow 4^(x) = 1 and 4^(x) = 16#

#Rightarrow 4^(x) = 4^(0) and 4^(x) = 4^(2)#

Using the laws of exponents:

#therefore x = 0 and x = 2#

Therefore, the solutions to the equation are #x = 0# and #x = 2#.