Y=-x-2
y=3x+2
multiply the first equation by 3: 3y=-3x-6
add up this equation with equation 2: 4y=-4, y=-1
-1=3x+2, x=-1
so the solution point is (-1,-1)
If you want to find the product it would be 6x^2-7xy^2+y^4
Just from the figure,
As x decreases, y approaches 0
As x increases, y increases without bound