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log(5x-7)/log(2)-log(5)/log(2)=log(21)/log(2) la ecuación

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Solución numérica:

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Solución

Ha introducido [src]
log(5*x - 7)   log(5)   log(21)
------------ - ------ = -------
   log(2)      log(2)    log(2)
$$\frac{\log{\left(5 x - 7 \right)}}{\log{\left(2 \right)}} - \frac{\log{\left(5 \right)}}{\log{\left(2 \right)}} = \frac{\log{\left(21 \right)}}{\log{\left(2 \right)}}$$
Solución detallada
Tenemos la ecuación
$$\frac{\log{\left(5 x - 7 \right)}}{\log{\left(2 \right)}} - \frac{\log{\left(5 \right)}}{\log{\left(2 \right)}} = \frac{\log{\left(21 \right)}}{\log{\left(2 \right)}}$$
$$\frac{\log{\left(5 x - 7 \right)}}{\log{\left(2 \right)}} = \frac{\log{\left(5 \right)}}{\log{\left(2 \right)}} + \frac{\log{\left(21 \right)}}{\log{\left(2 \right)}}$$
Devidimos ambás partes de la ecuación por el multiplicador de log =1/log(2)
$$\log{\left(5 x - 7 \right)} = \left(\frac{\log{\left(5 \right)}}{\log{\left(2 \right)}} + \frac{\log{\left(21 \right)}}{\log{\left(2 \right)}}\right) \log{\left(2 \right)}$$
Es la ecuación de la forma:
log(v)=p

Por definición log
v=e^p

entonces
$$5 x - 7 = e^{\frac{\frac{\log{\left(5 \right)}}{\log{\left(2 \right)}} + \frac{\log{\left(21 \right)}}{\log{\left(2 \right)}}}{\frac{1}{\log{\left(2 \right)}}}}$$
simplificamos
$$5 x - 7 = e^{\left(\frac{\log{\left(5 \right)}}{\log{\left(2 \right)}} + \frac{\log{\left(21 \right)}}{\log{\left(2 \right)}}\right) \log{\left(2 \right)}}$$
$$5 x = 7 + e^{\left(\frac{\log{\left(5 \right)}}{\log{\left(2 \right)}} + \frac{\log{\left(21 \right)}}{\log{\left(2 \right)}}\right) \log{\left(2 \right)}}$$
$$x = \frac{7}{5} + \frac{e^{\left(\frac{\log{\left(5 \right)}}{\log{\left(2 \right)}} + \frac{\log{\left(21 \right)}}{\log{\left(2 \right)}}\right) \log{\left(2 \right)}}}{5}$$
Gráfica
Respuesta rápida [src]
x1 = 112/5
$$x_{1} = \frac{112}{5}$$
x1 = 112/5
Suma y producto de raíces [src]
suma
112/5
$$\frac{112}{5}$$
=
112/5
$$\frac{112}{5}$$
producto
112/5
$$\frac{112}{5}$$
=
112/5
$$\frac{112}{5}$$
112/5
Respuesta numérica [src]
x1 = 22.4
x1 = 22.4