Question

Se x= 3y+12 e y= 2x, então o valor de x+y ?

Answer 1

x= 3y+12

y= 2x

x+y =

( 3y + 12 ) + y =

4y = - 12

$y=\frac{-12}{4}$

y = - 3

x= 3y+12

x = 3 . ( - 3 ) + 12

x = - 9 + 12

x = 3

x + y =

3 + (-3) =

3 - 3 = 0