Parabola

Find a+b+c. 

Hello Guest!

The functional equation of the parabola shown is:

$f(x)=(x-1)^2-4=x^2-2x-3$

$a=1\\b=-2\\ c=-3\\ \color{blue}a+b+c=-4$

  !

Let $f(x)=ax^2+bx+c$. Note that $f(1) = a \cdot 1^2 + b \cdot 1 + c = a + b + c$, so $a + b + c = f(1) = \boxed{-4}$.