Answer
Vertex: $(-1,4)$
x-intercept: $(-3,0),(-1,0)$
axis of symmetry: $x=-1$
Work Step by Step
$f(x)=-(x^2+2x-3)=-x^2-2x+3$
$a=-1,~~b=-2,~~c=3$
Vertex:
$\frac{-b}{2a}=\frac{-(-2)}{2(-1)}=-1$
$f(\frac{-b}{2a})=-(-1)^2-2(-1)+3=-1+2+3=4$
x-intercept:
$x_1=\frac{-(-2)+\sqrt {(-2)^2-4(-1)3}}{2(-1)}=\frac{2+\sqrt {16}}{-2}=-3$
$x_2=\frac{-(-2)-\sqrt {(-2)^2-4(-1)3}}{2(-1)}=\frac{2-\sqrt {16}}{-2}=1$
