Question

Resolva o sistema a seguir:
{ log(x+1) - log y = 3 log 2
{ x-4y= 7

Answer 1

$Log ( x + 1 ) - Logy = 3Log2 \\ Log \frac{x + 1}{y} = 3Log2 \\ 3 = \frac{ Log \frac{x + 1}{y} }{Log2} \\ Log_{2} \frac{x + 1}{y} = 3 \\ \frac{x + 1}{y} = 2^3 \\ x + 1 = 8y \\ x = 8y - 1$

No segundo :

$x - 4y = 7 \\ 8y - 1 - 4y = 7 \\ 4y = 8 \\ y = 2$

$x = 8y - 1 = 16 - 1 = 15$