Question

O calculo de

X+2y=40

2x+y=30

Answer 1

x+2y=40         2y=40-x      y=40-x/2 
2x+y=30   

2x+40-x/2 =30

4x+40-x=60

3x=60-40

3x=20

x=20/3

Y=40-20/3 : 2 

Y=120-20/3 : 2 

Y=100/3 : 2/1 

Y= 100/6

S=[X 20/3 ,Y 100/6]