ttkn hp dari sp x^2-5x-y = 2 x^2-4x-y=1

x² - 5x - y = 2
x² - 4x - y = 1
____________-
- 9x = 1
x = -1/9

(-1/9)² - 5(-1/9) - y = 1
1/81 + 5/9 = y + 1
46/81 - 1 = y
y = 127/81