tolong jwb no 8 terimakasih. dengan cara

x-2y=10
-2y = 10 - x
y = 10/(-2) - 1/(-2) x
y = -5 + 1/2 x

y = x^2 + 2x - 15

-5 + 1/2 x = x^2 + 2x - 15
x^2 + 2x - 1/2 x -15 + 5 = 0
x^2 +3/2 x - 10 = 0
2x^2 + 3x - 20 = 0
(2x - 5) (x + 4)
2x-5 = 0
     x = 5/2
atau
x+4=0
    x=-4
Hp={-4,5/2}