Question

4 elevado a x - 2 elevado a x = 12

Answer 1

4^x - 2^x = 12
(2^2)^x - 2^x = 12
(2^x)^2 - 2^x = 12
2^x = y

Y^2 - y - 12 = 0
A = 1; B = - 1; C = - 12

/\= b^2-4ac
/\= (-1)^2 - 4.1.(-12)
/\= 1 + 48
/\ = 49
Y = (- b +/- \/ /\)/2a
Y = [-(-1)+/- \/49]/2.1
Y = (1 +/- 7)/2
Y' = (1+7)/2= 8/2= 4
Y" = (1-7)/2= -6/2= - 3

2^x = y
2^x = - 3 (não serve)

2^x = y
2^x = 4
2^x = 2^2
X = 2

R.: x = 2