Question

1)Resolva:

x + 5y = 60
x - y = 20

2)Resolva:

2x + 10y = 120
2x - 2y = 40

Answer 1

1) x=20+y
20+y+5y=60
20+6y=60
6y=60-20
6y=40
y=40/6
y=6,66
x=20+6,66
x=26,66

2)2x-2y=40
2x=40-2y
x=40/2-2y
x=20-2y
2.(20-2y)+10y=120
40-4y+10y=120
6y=120-40
6y=80
y=80/6
y=13,33
2x+2.(13,33)=40
2x+26,66=40
2x=40-26,66
2x=13,34
x=13,34/2
x=6,67