Question

sistemas
2x+y=10
x+3y=15

Answer 1

2x + y = 10 ----- y = 10 - 2x
x + 3y = 15
x + 3 × (10 - 2x) = 15
x + 30 - 6x = 15
x - 6x = 15 - 30
-5x = -15 ____ × (-1)
5x = 15
x = 3