Question

x +y =7
3( y– x )= -9

Answer 1

Resposta:

x+y=7

3(y-x)=-9

x+y=7 (3)

-3x+3y=-9

3x+3y=21

-3x+3y=-9

6y=12

y=12/6

y=2

x+y=7

x+2=7

x=7-2

x=5