Deci means 1/10 of a unit in the metric system.
E.g decimeter = (1/10) meter
x + 3y= 4
-2x+ y= -1 (-2x from the other side)
2x+ 6y= 8 (multiply by 2)
-2x+ y= -1
7y =7
y= 1
x+ 3(1)= 4 (you do this to find the y)
x+ 3= 4
x= 1 (-3 from the other side)
x= 1 y=1 (1,1)
Conic section is about the best it can get