Question

) Resolva as
equações logarítmicas:

a) log3
(x2 + 3x -1) = 2                                                                                                         b) log2
(3x + 1) = 4

Answer 1

$a)log_3(x^2+3x-1)=2 \\ \\ x^2+3x-1=3^2 \\\\ x^2+3x-1=9 \\ \\ x^2+3x-1-9=0 \\ \\ x^2+3x-10=0 \\ \\ x'=-5 \\ \\ x''=2$

S = {-5, 2}



$b)log_2(3x+1)=4 \\ \\ 3x+1=2^4 \\ \\ 3x+1=15 \\ \\ 3x=16-1 \\ \\ 3x=15 \\ \\ x=15:3 \\ \\ x=5$

S = {5}