Respuesta :

2x + y = 3
x = 2y - 1

replace 
x = 2y - 1 into 2x + y = 3
2x + y = 3
2(2y - 1) + y = 3
4y - 2 + y = 3
5y = 5
y = 1

x = 2y - 1 = 2(1) - 1 =1

answer: x = 1 and y = 1 or (1,1)

add your like terms then graph