Y=x2+5x+6 how to solve this problem

Y = x² + 5x + 6
x² + 5x + 6 = 0
x = -5 +/- √(5² - 4(1)(6))
                   2(2)
x = -5 +/- √(25 - 24)
                   4
x = -5 +/- √(1)
              4
x = -5 +/- 1
            4
x = -1 1/4 +/- 1/4
x = -1 1/4 + 1/4                          x = -1 1/4 - 1/4
x = -1                                          x = -1 1/2

y = x² + 5x + 6
y = (-1)² + 5(-1) + 6
y = 1 - 5 + 6
y = -4 + 6
y = 2
(x, y) = (-1, 2)
or
y = x² + 5x + 6
y = (-1 1/2)² + 5(-1 1/2) + 6
y = -2 1/4 - 7 1/2 + 6
y = -2 1/4 - 1 1/2
y = -3 3/4
(x, y) = (-1 1/2, -3 3/4)

When i did the math i got 11 cm