Question

Resuelve
Log (x^2-15x)=2
Log5 x-1=log5 (x-64)
Log9 (x+1)-log9 (1-x)=log9 (2x+3)

Answer 1

Log (x^2-15x)=2
(x^2-15x)=10^2
x^2-15x=100
x^2-15x-100=0
(x-20)(x+5)=0
x=20 y. x=-5
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Log5 x-1=log5 (x-64)
log5 (x-1)-log5(x-64)=0
(x-1)-(x-64)=0
x-1-x+64=0
-1+64=0
no existe solucion


Log9 (x+1)-log9 (1-x)=log9 (2x+3)
log9 (x+1)/(1-x)=log9 (2x+3)
(x+1)=(1-x)(2x+3)
x+1=2x+3-2x^2-3x
2x^2+2x-2=0
x^2+x-1=0
se aplica ecuacion general
y que da
x = raiz(5)/2-1/2

x=
x = -1/2-raiz(5)/2