Question

find the line of symmetry without graphing.
f(x)=-(x+4)^2-4

Answer 1

Vertex form of parabola is:
\[y = a(x - h)² + k\]
with vertex at (h, k) and
a > 0 means upwards open
a < 0 means downwards open

So
\[f(x) = -(x - 2)² + 2\]
is downwards open parabola with vertex at (2, 2); line of symmetry:
x = 2

Answer 2

simplify the above equation and rewrite the quadratic in it's standard form ax^2 + bx + c.

compare with the std. form and find out a,b,c.

the line of symmetry ---> x=-b/2a