Question

X + y = 3 -2x + 4y = 6

Answer 1

I'm assuming this is a system of equations you want solved so,

x = -y + 3

-2(-y+3)+4y = 6
2y - 6 + 4y = 6
6y = 12
y = 2

x + 2 = 3
x = -1

(-1,2)

Answer 2

2X+2Y=6
-2X+4Y=6

6Y=12
Y=2

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

x=1，y=2