We notice that 16=4^2!
We'll
re-write the equation in this manner:
2*(4^2)^x - 4^x -
1=0
We'll substitute 4^x by another variable,
t.
2*t^2 - t - 1=0
t1=[1+sqrt
(1+4*2)]/4
t1=[1+sqrt
(9)]/4
t1=(1+3)/4
t1=1
t2=[1-sqrt
(1+4*2)]/4
t2=(1-3)/4
t2=-1/2
We
didn't find the values of x,
yet!
4^x=1
4^x=4^0
Since
the bases are matching, we'll apply one to one property:
x
= 0
4^x=-1/2
The exponential
4^x is always positive, for any value of x, so, we'll reject the second
solution.
The equation has just one solution.
The only solution is x= 0.
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