Question

calcule
a) x=y
x+2y=20


b) x=y-2
2x+y=-1


façam a conta pfv

Answer 1

a)y+2y=20
3y=20
y=20/3
y=6,66       x=6,66

b)2(y-2)+y=-1
2y-4+y=-1
3y-4=-1
3y=-1+4
3y=-3
y=-1            
 
  x=-1-2 
x=-3