Question

quanto é $<var>\frac{4}{4+x}=20</var>$

Answer 1

 

80 + 20 x = 4

 

20x = -76

x = -76 / 20

 

x= -3,8

Answer 2

$<var>\frac{4}{4+x} = 20</var>$

 

$<var>4 = 20 (4+x)</var>$

 

$<var>4 = 80 + 20x</var>$

 

$<var>4-80 = 20x</var>$

 

$<var>-76 = 20x</var>$

 

$<var>\frac{-76}{20} = x</var>$

 

Simplificando por 4

$\boxed{<var>x = -\frac{19}{5}}</var>$