y = -x² - 4x - 3

a < 0 so it is n-shaped.

Max value is when x = -(-4)/-2 = -2

So the maximum point is (-2, 1)

-x² - 4x - 3 = 0 when

x² + 4x + 3 = 0

(x + 1)(x + 3) = 0

So x-axis intercepts are x = -1 and x = -3.