1) y = 2x^2 - 11x +5
2x^2 - 11x + 5 = - 7
2x^2 - 11x + 5 +7 = 0
2x^2 - 11x + 12 = 0
D = 121 + 48 = 169 = 13^2
x1 = 11 -13/4 = -0.5
x2 = 11+13/4 = 6
y = 3x^2 - 7x - 8
3x^2 -7x -8 = -2
3x^2 - 7x - 8 + 2 = 0
3x^2 -7x - 6 = 0
D = 49 + 72 = 121 = 11^2
x1 = 7 - 11/6 = -2/3
x2 = 7 + 11/6 = 3