Question

Resolva a equação: ​

Answer 1

Resposta:

log₇ 2 + log₇ (x²+4x)  = log₇ 9

log 2 /log 7 + log(x²+4x)/log 7 = log 9/log 7

log 2  + log(x²+4x) = log 9

log 2*(x²+4x) = log 9

2*(x²+4x) =9

2x²+8x-9=0

x'=-2-√17/2

x'=-2+√17/2

Verificando:

x²+4x =(-2-√17/2)²+4*(-2-√17/2) =1/4 >0

x²+4x =(-2+√17/2)+4*(-2+√17/2) > 0