Y= x2 + 2x − 1 y − 3x = 5 the pair of points representing the solution set of this system of equations is_ and _ .

The first equation is Y = x2 + 2x -1. 
The second equation is y -3x = 5 or y=3x+5

We know that Y=y, there we can solve for the solution set and it is shown below:
x2 + 2x -1 = 3x + 5
x2 +2x-3x -1-5= 0
x2 -x -6 = 0
(x -3) (x+2) = 0
x - 3=0   -> x=3
x+2 =0   -> x=-2

If x = 3, we have y = 3x+5 , y =(3*3) +5, y =14
(3, 14)
If x = -2, we have y= 3(-2) +5 , y=- -6+5, y= -1
(-2 , -1)

Therefore, the solution set of this system of equations is "(3,14)" and "(-2, -1)".